Flutter源碼分析之初始化篇一(android)
前言
回想在公司工做拿到的第一個項目是一個flash遊戲項目，在那個時候flash遊戲很是流行，尚未被html5取代的跡象。遊戲程序架構採用的是後端mfc+前端flash框架，整個項目代碼20萬行，就我本身一我的開發。公司的要求是能修改、增長遊戲的功能。當時我雖然有一點mfc的基礎，可是遊戲沒有接觸過、flash的actionscript3更是一竅不通。那怎麼辦呢？學唄。因而通過一兩個月的各類畫uml圖、流程圖、寫僞代碼等等一系列的理解學習，發現不但理解了後端、前端的工做原理，甚至能夠開始擼框架了。那個時候整天跟人吹牛，如今想起來仍是以爲十分的有趣。一個看似龐大的體系從一竅不通到完全掌握，這個過程只要經歷一遍，以後就以爲沒有什麼問題是解決不了的。html
flutter在實現上破天荒的沒有采用目前的各類成熟視圖體系，而是採用了本身構建一套視圖體系，用gpu加速，因此性能高、界面流暢。對此，表示十分的感興趣。那麼要完全的挖掘一個框架的本質，就只有研究源碼這麼一條道路。從今天起，預計花一到兩個月的時間來分析flutter的源碼，在這裏給你們分享下研究的過程。前端
這一系列的文章應該會很是長，研究源碼須要耐心，不是麼。html5
文章結構
筆者認爲這樣android
- 分析代碼
- 提出這段代碼問題，應該在後續的分析中解決
- 解決問題，分析前面的問題哪些是解決的
- 總結代碼
- 在階段性分析後給出圖
flutter源碼分析之FlutterActivity
實現接口分析
/// activity實現了三個接口
public class FlutterActivity extends Activity implements Provider, PluginRegistry, ViewFactory {
/// 視圖提供類，一個方法getFlutterView
public interface Provider {
FlutterView getFlutterView();
}
/// 插件註冊
public interface PluginRegistry {
/// 註冊一個插件
PluginRegistry.Registrar registrarFor(String var1);
/// 是否有這個插件
boolean hasPlugin(String var1);
/// 插件發佈值
<T> T valuePublishedByPlugin(String var1);
/// 下面開始爲插件生命週期回調
public interface PluginRegistrantCallback {
void registerWith(PluginRegistry var1);
}
/// 顯然是視圖銷燬的回調
public interface ViewDestroyListener {
boolean onViewDestroy(FlutterNativeView var1);
}
//// 不知道幹啥，先留着
public interface UserLeaveHintListener {
void onUserLeaveHint();
}
//// activity生命週期回調之onNewIntent
public interface NewIntentListener {
boolean onNewIntent(Intent var1);
}
//// activity生命週期回調之onActivityResult
public interface ActivityResultListener {
boolean onActivityResult(int var1, int var2, Intent var3);
}
//// activity生命週期回調之onRequestPermissionsResult
public interface RequestPermissionsResultListener {
boolean onRequestPermissionsResult(int var1, String[] var2, int[] var3);
}
/// 插件的註冊者，至關於插件的宿主。
public interface Registrar {
Activity activity();
Context context();
Context activeContext();
/// 這個BinaryMessager還不知道幹啥
BinaryMessenger messenger();
/// TextureRegistry不清楚
TextureRegistry textures();
/// 獲取視圖
FlutterView view();
/// 尋找資源
String lookupKeyForAsset(String var1);
/// 尋找資源
String lookupKeyForAsset(String var1, String var2);
/// 發佈值，與上面的valuePublishedByPlugin對應
PluginRegistry.Registrar publish(Object var1);
/// 增長生命週期回調
PluginRegistry.Registrar addRequestPermissionsResultListener(PluginRegistry.RequestPermissionsResultListener var1);
/// 增長生命週期回調
PluginRegistry.Registrar addActivityResultListener(PluginRegistry.ActivityResultListener var1);
PluginRegistry.Registrar addNewIntentListener(PluginRegistry.NewIntentListener var1);
/// 增長生命週期回調
PluginRegistry.Registrar addUserLeaveHintListener(PluginRegistry.UserLeaveHintListener var1);
/// 增長生命週期回調
PluginRegistry.Registrar addViewDestroyListener(PluginRegistry.ViewDestroyListener var1);
}
}
/// 視圖工廠
public interface ViewFactory {
/// 建立flutterView
FlutterView createFlutterView(Context var1);
//// 建立nativeview
FlutterNativeView createFlutterNativeView();
/// 暫時搞不清楚幹啥的，先留着
boolean retainFlutterNativeView();
}
問題
- （1）FlutterNativeView和FlutterView有啥區別和聯繫
- （2）UserLeaveHintListener做用?
- （3）ViewFactory#retainFlutterNativeView做用?
- （4）BinaryMessenger做用
- （5）TextureRegistry做用
這些問題在以後的分析中應該能解決。shell
Activity的生命週期分析
構造函數
///建立FlutterActivityDelegate
private final FlutterActivityDelegate delegate = new FlutterActivityDelegate(this, this);
private final FlutterActivityEvents eventDelegate;
private final Provider viewProvider;
private final PluginRegistry pluginRegistry;
public FlutterActivity() {
/// FlutterActivityDelegate實現了這三個接口，並賦值給三個變量，這樣調用起來更加清晰。
this.eventDelegate = this.delegate;
this.viewProvider = this.delegate;
this.pluginRegistry = this.delegate;
}
onCreate、onResume、onStop、onDestory、onPause、onNewIntent、onStart、onActivityResult、onRequestPermissionResult
///這裏都是由建立FlutterActivityDelegate代理執行,就不一一貼出來了
protected void onXXX() {
super.onXXX();
this.eventDelegate.onXXX();
}
建立FlutterView
值得注意的是這裏的三個回調，表示FlutterView是如何建立出來的。後端
public FlutterView getFlutterView() {
/// 有關的函數，只有這個由FlutterActivityDelegate代理執行
return this.viewProvider.getFlutterView();
}
public FlutterView createFlutterView(Context context) {
return null;
}
public FlutterNativeView createFlutterNativeView() {
return null;
}
public boolean retainFlutterNativeView() {
return false;
}
FlutterActivity總結
- FlutterActivity的生命週期和各個方法實際上由FlutterActivityDelegate代理執行。
- 從Activity的源碼來看，已經清晰的看出FlutterActivity解決了生命週期的回調，插件管理，建立FlutterView以及相關的ui。
問題
- （6）FlutterView究竟如何建立的
- （7）retainFlutterNativeView有什麼做用
flutter源碼分析之FlutterActivityDelegate
仍是onCreate
/// 啓動參數解析
String[] args = getArgsFromIntent(this.activity.getIntent());
/// 等待並保證初始化完成
FlutterMain.ensureInitializationComplete(this.activity.getApplicationContext(), args);
/// 建立flutterView,注意到上面默認的返回null
this.flutterView = this.viewFactory.createFlutterView(this.activity);
if (this.flutterView == null) {
/// 默認走這裏,createFlutterNativeView默認返回null
FlutterNativeView nativeView = this.viewFactory.createFlutterNativeView();
//實際建立了FlutterView
this.flutterView = new FlutterView(this.activity, (AttributeSet)null, nativeView);
// 設置layout，並添加到當前activity，做爲主視圖
this.flutterView.setLayoutParams(matchParent);
this.activity.setContentView(this.flutterView);
//建立啓動ui
this.launchView = this.createLaunchView();
if (this.launchView != null) {
//若是有建立啓動ui成功，那麼增長到當前activity上面
this.addLaunchView();
}
}
看下FlutterMain.ensureInitializationComplete緩存
public static void ensureInitializationComplete(Context applicationContext, String[] args) {
// 保證ui線程運行
if (Looper.myLooper() != Looper.getMainLooper()) {
throw new IllegalStateException("ensureInitializationComplete must be called on the main thread");
} else if (!sInitialized) {
try {
// 等待完成，這裏有個疑問點，sResourceExtractor是何時建立的
sResourceExtractor.waitForCompletion();
// 繼續解析參數
List<String> shellArgs = new ArrayList();
shellArgs.add("--icu-data-file-path=" + new File(PathUtils.getDataDirectory(applicationContext), "icudtl.dat"));
if (args != null) {
Collections.addAll(shellArgs, args);
}
if (sIsPrecompiledAsSharedLibrary) {
shellArgs.add("--aot-shared-library-path=" + new File(PathUtils.getDataDirectory(applicationContext), sAotSharedLibraryPath));
} else {
if (sIsPrecompiledAsBlobs) {
shellArgs.add("--aot-snapshot-path=" + PathUtils.getDataDirectory(applicationContext));
} else {
shellArgs.add("--cache-dir-path=" + PathUtils.getCacheDirectory(applicationContext));
shellArgs.add("--aot-snapshot-path=" + PathUtils.getDataDirectory(applicationContext) + "/" + sFlutterAssetsDir);
}
shellArgs.add("--vm-snapshot-data=" + sAotVmSnapshotData);
shellArgs.add("--vm-snapshot-instr=" + sAotVmSnapshotInstr);
shellArgs.add("--isolate-snapshot-data=" + sAotIsolateSnapshotData);
shellArgs.add("--isolate-snapshot-instr=" + sAotIsolateSnapshotInstr);
}
if (sSettings.getLogTag() != null) {
shellArgs.add("--log-tag=" + sSettings.getLogTag());
}
// 查找bundle
String appBundlePath = findAppBundlePath(applicationContext);
// native初始化，參數爲解析的全部啓動參數和一個bundle的路徑
nativeInit(applicationContext, (String[])shellArgs.toArray(new String[0]), appBundlePath);
sInitialized = true;
} catch (Exception var4) {
Log.e("FlutterMain", "Flutter initialization failed.", var4);
throw new RuntimeException(var4);
}
}
}
///這裏的nativeInit是jni調用，實際做用是? 這裏我猜是初始化dart環境，並初始化加載bundle，相似初始化js環境，並加載jsbundle private static native void nativeInit(Context var0, String[] var1, String var2);
看下:架構
sResourceExtractor.waitForCompletion();
sResourceExtractor是啥時候建立的？那麼這裏全局搜索了一番，瞭解到到FlutterMain#startInitialization這個方法是在FlutterApplication中調用的，因此先看下Application。這裏先提出疑問，以後解決。app
問題
- (8)sResourceExtractor.waitForCompletion();在幹什麼？
- (9)new FlutterView(this.activity, (AttributeSet)null, nativeView);這裏是否能夠解釋前面的問題（1）
- (10) nativeInit做用？bundle是什麼，如何加載？
flutter源碼分析之FlutterApplication
原本這個Application應該是第一個分析的，可是首先用戶看到的flutter建立的example裏面暴露的第一個類應該就是FlutterActivity。FlutterApplication是在AndroidManifest中定義的，因此筆者一開始沒有注意到，這裏插個隊補上。框架
public class FlutterApplication extends Application {
private Activity mCurrentActivity = null;
public FlutterApplication() {
}
// 顯然這裏進行了全局初始化
@CallSuper
public void onCreate() {
super.onCreate();
FlutterMain.startInitialization(this);
}
public Activity getCurrentActivity() {
return this.mCurrentActivity;
}
// 設置當前的Activity
public void setCurrentActivity(Activity mCurrentActivity) {
this.mCurrentActivity = mCurrentActivity;
}
}
FlutterMain.startInitialization
public static void startInitialization(Context applicationContext, FlutterMain.Settings settings) {
if (Looper.myLooper() != Looper.getMainLooper()) {
throw new IllegalStateException("startInitialization must be called on the main thread");
} else if (sSettings == null) {
sSettings = settings;
long initStartTimestampMillis = SystemClock.uptimeMillis();
initConfig(applicationContext);
initAot(applicationContext);
initResources(applicationContext);
System.loadLibrary("flutter");
long initTimeMillis = SystemClock.uptimeMillis() - initStartTimestampMillis;
nativeRecordStartTimestamp(initTimeMillis);
}
}
Setting
這裏的Setting很是簡單,只是提供了日誌的tag,那麼這個logTag在哪裏用？又是一個疑問。
public static class Settings {
private String logTag;
public Settings() {
}
public String getLogTag() {
return this.logTag;
}
public void setLogTag(String tag) {
this.logTag = tag;
}
}
initConfig
initConfig,這個函數主要用於初始化配置
private static void initConfig(Context applicationContext) {
try {
Bundle metadata = applicationContext.getPackageManager().getApplicationInfo(applicationContext.getPackageName(), 128).metaData;
if (metadata != null) {
sAotSharedLibraryPath = metadata.getString(PUBLIC_AOT_AOT_SHARED_LIBRARY_PATH, "app.so");
sAotVmSnapshotData = metadata.getString(PUBLIC_AOT_VM_SNAPSHOT_DATA_KEY, "vm_snapshot_data");
sAotVmSnapshotInstr = metadata.getString(PUBLIC_AOT_VM_SNAPSHOT_INSTR_KEY, "vm_snapshot_instr");
sAotIsolateSnapshotData = metadata.getString(PUBLIC_AOT_ISOLATE_SNAPSHOT_DATA_KEY, "isolate_snapshot_data");
sAotIsolateSnapshotInstr = metadata.getString(PUBLIC_AOT_ISOLATE_SNAPSHOT_INSTR_KEY, "isolate_snapshot_instr");
sFlx = metadata.getString(PUBLIC_FLX_KEY, "app.flx");
sSnapshotBlob = metadata.getString(PUBLIC_SNAPSHOT_BLOB_KEY, "snapshot_blob.bin");
sFlutterAssetsDir = metadata.getString(PUBLIC_FLUTTER_ASSETS_DIR_KEY, "flutter_assets");
}
} catch (NameNotFoundException var2) {
throw new RuntimeException(var2);
}
}
這裏能夠看到flutter的定製選項，能夠在androd的meta裏面定義
- sAotSharedLibraryPath
- sAotVmSnapshotData
- sAotVmSnapshotInstr
- sAotIsolateSnapshotData
- sAotIsolateSnapshotInstr
- sFlx
- sSnapshotBlob
- sFlutterAssetsDir
initAot
關於aot，這裏有幾篇博文介紹：
https://www.cnblogs.com/zengm...
https://www.cnblogs.com/tinyt...
AOT是一種靜態編譯技術，與JIT對應
private static void initAot(Context applicationContext) {
// 列出全部的assets文件夾中的資源
Set<String> assets = listRootAssets(applicationContext);
//
sIsPrecompiledAsBlobs = assets.containsAll(Arrays.asList(sAotVmSnapshotData, sAotVmSnapshotInstr, sAotIsolateSnapshotData, sAotIsolateSnapshotInstr));
sIsPrecompiledAsSharedLibrary = assets.contains(sAotSharedLibraryPath);
// 意思是兩個不能同時存在?
if (sIsPrecompiledAsBlobs && sIsPrecompiledAsSharedLibrary) {
throw new RuntimeException("Found precompiled app as shared library and as Dart VM snapshots.");
}
}
initResources
private static void initResources(Context applicationContext) {
// 開始清理資源
(new ResourceCleaner(applicationContext)).start();
// 建立sResourceExtractor
sResourceExtractor = (new ResourceExtractor(applicationContext)).addResources(SKY_RESOURCES).addResource(fromFlutterAssets(sFlx)).addResource(fromFlutterAssets(sSnapshotBlob)).addResource(fromFlutterAssets(sAotVmSnapshotData)).addResource(fromFlutterAssets(sAotVmSnapshotInstr)).addResource(fromFlutterAssets(sAotIsolateSnapshotData)).addResource(fromFlutterAssets(sAotIsolateSnapshotInstr)).addResource(fromFlutterAssets("kernel_blob.bin")).addResource(fromFlutterAssets("platform.dill"));
// 增長資源
if (sIsPrecompiledAsSharedLibrary) {
sResourceExtractor.addResource(sAotSharedLibraryPath);
} else {
sResourceExtractor.addResource(sAotVmSnapshotData).addResource(sAotVmSnapshotInstr).addResource(sAotIsolateSnapshotData).addResource(sAotIsolateSnapshotInstr).addResource(sSnapshotBlob);
}
//開始
sResourceExtractor.start();
}
看下:
(new ResourceCleaner(applicationContext)).start(),做用是清理緩存
boolean result = name.startsWith(".org.chromium.Chromium.");
return result;
...
protected Void doInBackground(Void... unused) {
File[] var2 = this.mFilesToDelete;
int var3 = var2.length;
for(int var4 = 0; var4 < var3; ++var4) {
File file = var2[var4];
if (file.exists()) {
this.deleteRecursively(file);
}
}
}
看下:sResourceExtractor.start();
ResourceExtractor start() {
assert this.mExtractTask == null;
this.mExtractTask = new ResourceExtractor.ExtractTask();
this.mExtractTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, new Void[0]);
return this;
}
...
private void extractResources() {
File dataDir = new File(PathUtils.getDataDirectory(ResourceExtractor.this.mContext));
...
InputStream is = manager.open(asset);
Throwable var9 = null;
try {
OutputStream os = new FileOutputStream(output);
Throwable var11 = null;
...
while((count = is.read(buffer, 0, 16384)) != -1) {
os.write(buffer, 0, count);
}
...
}
...
public final class PathUtils {
...
public static String getDataDirectory(Context applicationContext) {
return applicationContext.getDir("Lflutter", 0).getPath();
}
...
}
這段代碼是將指定的assert文件夾中的文件拷貝到應用程序目錄中的flutter文件夾下，說明後續程序須要直接使用文件，而不是assert文件夾中的二進制。
native部分
System.loadLibrary("flutter");
nativeRecordStartTimestamp(initTimeMillis);
初始化native，並記錄時間,native的部分，這篇文章先不予考慮，專門在一個專題裏面寫。
問題
此次光看代碼比較難以理解，須要動態調試了
- （11）sIsPrecompiledAsBlobs && sIsPrecompiledAsSharedLibrary這兩個參數具體表明什麼含義，爲何不能同時存在？和flutter的hotload有關嗎，和flutter是調試版本仍是發佈版本有關嗎？
- （12）flutter中的so庫具體有哪些，有什麼做用？
解決問題
- (8)sResourceExtractor.waitForCompletion();在幹什麼？
此次顯然已經解決了前面的問題(8), FlutterActivity在啓動的時候，須要等待FlutterApplicaiton中的異步加載資源完畢
總結
FlutterApplication在onCreate的時候，初始化加載Flutter中的資源，含bundle、so庫等重要啓動資源，而在FlutterActivity的onCreate中，會等待FlutterApplication的這個過程完畢以後再進行下一步的初始化。
Flutter源碼分析建立FlutterView
這裏接着上面來分析FlutterView的建立過程:
public class FlutterView extends SurfaceView implements BinaryMessenger, TextureRegistry, AccessibilityStateChangeListener {
注意到FlutterView繼承了SurfaceView,關於SurfaceView，能夠參考幾篇博文理解：
https://blog.csdn.net/android...
https://www.cnblogs.com/zhang...
SurfaceView使用的繪圖線程不是ui線程，咱們平時使用的攝像頭、遊戲之類的要求圖形性能比較高的場景就靠它了。
看下構造函數:
this.nextTextureId = new AtomicLong(0L);
...
@Override
public TextureRegistry.SurfaceTextureEntry createSurfaceTexture() {
final SurfaceTexture surfaceTexture = new SurfaceTexture(0);
surfaceTexture.detachFromGLContext();
final SurfaceTextureRegistryEntry entry =
new SurfaceTextureRegistryEntry(nextTextureId.getAndIncrement(), surfaceTexture);
nativeRegisterTexture(mNativeView.get(), entry.id(), surfaceTexture);
return entry;
}
這裏使用到了SurfaceTexture,並執行了nativeRegisterTexture,關於SurfaceTexture,找到這麼幾篇博文:
https://www.cnblogs.com/wytig...
https://blog.csdn.net/hejjunl...
https://blog.csdn.net/u010949...
https://blog.csdn.net/tq08g2z...
https://blog.csdn.net/OnafioO...
https://blog.csdn.net/u010949...
https://blog.csdn.net/u010949...
基本上全是csdn的老文章！
這個SurfactTexture具體做用？先放放。
接着往下看:
this.mIsSoftwareRenderingEnabled = nativeGetIsSoftwareRenderingEnabled();
關於android的軟件渲染仍是硬件渲染:
https://blog.csdn.net/wlwl007...
https://blog.csdn.net/luoshen...
http://www.sohu.com/a/1605251...
繼續
this.mMetrics = new FlutterView.ViewportMetrics();
this.mMetrics.devicePixelRatio = context.getResources().getDisplayMetrics().density;
...
private void updateViewportMetrics() {
if (this.isAttached()) {
nativeSetViewportMetrics(this.mNativeView.get(), this.mMetrics.devicePixelRatio, this.mMetrics.physicalWidth, this.mMetrics.physicalHeight, this.mMetrics.physicalPaddingTop, this.mMetrics.physicalPaddingRight, this.mMetrics.physicalPaddingBottom, this.mMetrics.physicalPaddingLeft, this.mMetrics.physicalViewInsetTop, this.mMetrics.physicalViewInsetRight, this.mMetrics.physicalViewInsetBottom, this.mMetrics.physicalViewInsetLeft);
WindowManager wm = (WindowManager)this.getContext().getSystemService("window");
float fps = wm.getDefaultDisplay().getRefreshRate();
VsyncWaiter.refreshPeriodNanos = (long)(1.0E9D / (double)fps);
}
}
...
protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
this.mMetrics.physicalWidth = width;
this.mMetrics.physicalHeight = height;
this.updateViewportMetrics();
super.onSizeChanged(width, height, oldWidth, oldHeight);
}
public final WindowInsets onApplyWindowInsets(WindowInsets insets) {
this.mMetrics.physicalPaddingTop = insets.getSystemWindowInsetTop();
this.mMetrics.physicalPaddingRight = insets.getSystemWindowInsetRight();
this.mMetrics.physicalPaddingBottom = 0;
this.mMetrics.physicalPaddingLeft = insets.getSystemWindowInsetLeft();
this.mMetrics.physicalViewInsetTop = 0;
this.mMetrics.physicalViewInsetRight = 0;
this.mMetrics.physicalViewInsetBottom = insets.getSystemWindowInsetBottom();
this.mMetrics.physicalViewInsetLeft = 0;
this.updateViewportMetrics();
return super.onApplyWindowInsets(insets);
}
protected boolean fitSystemWindows(Rect insets) {
if (VERSION.SDK_INT <= 19) {
this.mMetrics.physicalPaddingTop = insets.top;
this.mMetrics.physicalPaddingRight = insets.right;
this.mMetrics.physicalPaddingBottom = 0;
this.mMetrics.physicalPaddingLeft = insets.left;
this.mMetrics.physicalViewInsetTop = 0;
this.mMetrics.physicalViewInsetRight = 0;
this.mMetrics.physicalViewInsetBottom = insets.bottom;
this.mMetrics.physicalViewInsetLeft = 0;
this.updateViewportMetrics();
return true;
} else {
return super.fitSystemWindows(insets);
}
}
private boolean isAttached() {
return this.mNativeView != null && this.mNativeView.isAttached();
}
這裏又涉及到幾個概念，基本都不怎麼經常使用:
WindowInsets,onApplyWindowInsets:
https://blog.csdn.net/me_touc...
fitSystemWindows:
https://blog.csdn.net/ys40897...
static final class ViewportMetrics {
float devicePixelRatio = 1.0F;
int physicalWidth = 0;
int physicalHeight = 0;
int physicalPaddingTop = 0;
int physicalPaddingRight = 0;
int physicalPaddingBottom = 0;
int physicalPaddingLeft = 0;
int physicalViewInsetTop = 0;
int physicalViewInsetRight = 0;
int physicalViewInsetBottom = 0;
int physicalViewInsetLeft = 0;
ViewportMetrics() {
}
}
這段代碼的意思顯然是適配窗口大小的變化，並在恰當的時候更新mMetrics，並設置到native中
private static native void nativeSetViewportMetrics(long nativePlatformViewAndroid,
float devicePixelRatio, int physicalWidth, int physicalHeight, int physicalPaddingTop,
int physicalPaddingRight, int physicalPaddingBottom, int physicalPaddingLeft,
int physicalViewInsetTop, int physicalViewInsetRight, int physicalViewInsetBottom,
int physicalViewInsetLeft);
繼續：
Activity activity = (Activity)this.getContext();
if (nativeView == null) {
this.mNativeView = new FlutterNativeView(activity.getApplicationContext());
} else {
this.mNativeView = nativeView;
}
NativeView是什麼？
public class FlutterNativeView implements BinaryMessenger {
...
public FlutterNativeView(Context context) {
this.mContext = context;
// 插件管理
this.mPluginRegistry = new FlutterPluginRegistry(this, context);
this.attach(this);
this.assertAttached();
// 消息管理
this.mMessageHandlers = new HashMap();
}
...
//涉及到和native打交道
private static native long nativeAttach(FlutterNativeView var0);
private static native void nativeDestroy(long var0);
private static native void nativeDetach(long var0);
private static native void nativeRunBundleAndSnapshot(long var0, String var2, String var3, String var4, boolean var5, AssetManager var6);
private static native void nativeRunBundleAndSource(long var0, String var2, String var3, String var4);
private static native void nativeSetAssetBundlePathOnUI(long var0, String var2);
private static native String nativeGetObservatoryUri();
private static native void nativeDispatchEmptyPlatformMessage(long var0, String var2, int var3);
private static native void nativeDispatchPlatformMessage(long var0, String var2, ByteBuffer var3, int var4, int var5);
private static native void nativeInvokePlatformMessageEmptyResponseCallback(long var0, int var2);
private static native void nativeInvokePlatformMessageResponseCallback(long var0, int var2, ByteBuffer var3, int var4);
}
NativeView顯然是一個插件、消息的管理類，並與native打交道，那麼和FlutterView的關係，顯然一個負責展現，一個負責交互。這裏解決了問題(1)
再往下看
this.mSurfaceCallback = new Callback() {
public void surfaceCreated(SurfaceHolder holder) {
FlutterView.this.assertAttached();
FlutterView.nativeSurfaceCreated(FlutterView.this.mNativeView.get(), holder.getSurface(), color);
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
FlutterView.this.assertAttached();
FlutterView.nativeSurfaceChanged(FlutterView.this.mNativeView.get(), width, height);
}
public void surfaceDestroyed(SurfaceHolder holder) {
FlutterView.this.assertAttached();
FlutterView.nativeSurfaceDestroyed(FlutterView.this.mNativeView.get());
}
};
this.getHolder().addCallback(this.mSurfaceCallback);
這裏監聽了SurfaceView的生命週期,並調用native
this.mAccessibilityManager = (AccessibilityManager)this.getContext().getSystemService("accessibility");
this.mActivityLifecycleListeners = new ArrayList();
this.mFirstFrameListeners = new ArrayList();
this.mFlutterLocalizationChannel = new MethodChannel(this, "flutter/localization", JSONMethodCodec.INSTANCE);
this.mFlutterNavigationChannel = new MethodChannel(this, "flutter/navigation", JSONMethodCodec.INSTANCE);
this.mFlutterKeyEventChannel = new BasicMessageChannel(this, "flutter/keyevent", JSONMessageCodec.INSTANCE);
this.mFlutterLifecycleChannel = new BasicMessageChannel(this, "flutter/lifecycle", StringCodec.INSTANCE);
this.mFlutterSystemChannel = new BasicMessageChannel(this, "flutter/system", JSONMessageCodec.INSTANCE);
this.mFlutterSettingsChannel = new BasicMessageChannel(this, "flutter/settings", JSONMessageCodec.INSTANCE);
PlatformPlugin platformPlugin = new PlatformPlugin(activity);
MethodChannel flutterPlatformChannel = new MethodChannel(this, "flutter/platform", JSONMethodCodec.INSTANCE);
flutterPlatformChannel.setMethodCallHandler(platformPlugin);
this.addActivityLifecycleListener(platformPlugin);
this.mImm = (InputMethodManager)this.getContext().getSystemService("input_method");
this.mTextInputPlugin = new TextInputPlugin(this);
this.setLocale(this.getResources().getConfiguration().locale);
this.setUserSettings();
這段代碼註冊了一些Flutter的自帶插件，主要用於輸入、生命週期、國際化等系統相關的插件，有時間再一個一個分析，先放放。
問題
- (13)native中的初始化流程？
- (14)這裏並無看到一行代碼有和繪製圖形有關，那麼在哪裏調用？是否都是在native中調用，怎麼調用的？
解決問題
- （1）FlutterNativeView和FlutterView有啥區別和聯繫
本篇總結
所有問題:
- (1)
FlutterNativeView和FlutterView有啥區別和聯繫 - (2)UserLeaveHintListener做用?
- (3)ViewFactory#retainFlutterNativeView做用?
- (4)BinaryMessenger做用
- (5)TextureRegistry做用
- (6)FlutterView究竟如何建立的
- (7)retainFlutterNativeView有什麼做用
- (8)
sResourceExtractor.waitForCompletion();在幹什麼？ - (9)
new FlutterView(this.activity, (AttributeSet)null, nativeView);這裏是否能夠解釋前面的問題(1) - (10) nativeInit做用？bundle是什麼，如何加載？
- (11)sIsPrecompiledAsBlobs && sIsPrecompiledAsSharedLibrary這兩個參數具體表明什麼含義，爲何不能同時存在？和flutter的hotload有關嗎，和flutter是調試版本仍是發佈版本有關嗎？
- (12)flutter中的so庫具體有哪些，有什麼做用？
- (13)native中的初始化流程？
- (14)這裏並無看到一行代碼有和繪製圖形有關，那麼在哪裏調用？是否都是在native中調用，怎麼調用的？
大部分問題在這裏都解釋不了，這裏先用一張圖表示一下啓動流程:
若有疑問，請加qq羣854192563討論
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