Android 使用WindowManager實現懸浮窗及源碼解析
使用
效果預覽
Demo結構
一個Activity、一個Service和兩個佈局文件。佈局十分簡單，這裏就不貼了，大概描述下。activity_main.xml中倆按鈕，layout_window.xml中一個TextView。ok，首先看下MainActivity。MainActivity中只有倆按鈕，點擊啓動WindowService，點擊中止WindowService。沒啥好說的。直接看WindowService。html
/**
* @author CSDN 一口仨饃
*/
public class WindowService extends Service {
private final String TAG = this.getClass().getSimpleName();
private WindowManager.LayoutParams wmParams;
private WindowManager mWindowManager;
private View mWindowView;
private TextView mPercentTv;
private int mStartX;
private int mStartY;
private int mEndX;
private int mEndY;
@Override
public void onCreate() {
super.onCreate();
Log.i(TAG, "onCreate");
initWindowParams();
initView();
addWindowView2Window();
initClick();
}
private void initWindowParams() {
mWindowManager = (WindowManager) getApplication().getSystemService(getApplication().WINDOW_SERVICE);
wmParams = new WindowManager.LayoutParams();
// 更多type：https://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#TYPE_PHONE
wmParams.type = WindowManager.LayoutParams.TYPE_PHONE;
wmParams.format = PixelFormat.TRANSLUCENT;
// 更多falgs:https://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_NOT_FOCUSABLE
wmParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
wmParams.gravity = Gravity.LEFT | Gravity.TOP;
wmParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
wmParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
}
private void initView() {
mWindowView = LayoutInflater.from(getApplication()).inflate(R.layout.layout_window, null);
mPercentTv = (TextView) mWindowView.findViewById(R.id.percentTv);
}
private void addWindowView2Window() {
mWindowManager.addView(mWindowView, wmParams);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(TAG, "onStartCommand");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
super.onDestroy();
if (mWindowView != null) {
//移除懸浮窗口
Log.i(TAG, "removeView");
mWindowManager.removeView(mWindowView);
}
Log.i(TAG, "onDestroy");
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
在設置各類屬性以後，直接向WindowManager中添加mWindowView（也就是咱們本身的佈局layout_window.xml）。在此以前須要在AndroidManifest。xml中註冊Service和添加相應的限權。java
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.GET_TASKS" />
<service android:name=".WindowService"/>
如今點擊startBtn，桌面上已經能夠出現懸浮窗。可是沒有拖動啦點擊啦這些動做。小意思，重寫點擊事件。根據拖動距離，判斷是點擊仍是滑動。因爲onTouchEvent()的優先級比onClick高，拖動時在須要的攔截的地方，return true就ok了。具體以下：android
private void initClick() {
mPercentTv.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mStartX = (int) event.getRawX();
mStartY = (int) event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
mEndX = (int) event.getRawX();
mEndY = (int) event.getRawY();
if (needIntercept()) {
//getRawX是觸摸位置相對於屏幕的座標，getX是相對於按鈕的座標
wmParams.x = (int) event.getRawX() - mWindowView.getMeasuredWidth() / 2;
wmParams.y = (int) event.getRawY() - mWindowView.getMeasuredHeight() / 2;
mWindowManager.updateViewLayout(mWindowView, wmParams);
return true;
}
break;
case MotionEvent.ACTION_UP:
if (needIntercept()) {
return true;
}
break;
default:
break;
}
return false;
}
});
mPercentTv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (isAppAtBackground(WindowService.this)) {
Intent intent = new Intent(WindowService.this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
});
}
/**
* 是否攔截
* @return true:攔截;false:不攔截.
*/
private boolean needIntercept() {
if (Math.abs(mStartX - mEndX) > 30 || Math.abs(mStartY - mEndY) > 30) {
return true;
}
return false;
}
這裏在onClick中進行了一個程序先後臺的判斷操做，方法以下：緩存
/**
*判斷當前應用程序處於前臺仍是後臺
*/
private boolean isAppAtBackground(final Context context) {
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1);
if (!tasks.isEmpty()) {
ComponentName topActivity = tasks.get(0).topActivity;
if (!topActivity.getPackageName().equals(context.getPackageName())) {
return true;
}
}
return false;
}
至此爲止。懸浮窗已經顯示出來，點擊拖動事件也已經搞定。雖然和360懸浮窗差距還蠻大，可是剩下的只剩具體實現。像addView()，removeView()和動畫等等，這裏就再也不具體實現。本着知其然知其因此然的精神，下文是整個流程的源碼解析。session
源碼解析
初始化解析
在WindowService中經過getApplication().getSystemService(getApplication().WINDOW_SERVICE)獲取到一個WindowManager，姑且稱這麼過程爲初始化。app
源碼位置：frameworks/base/core/Java/Android/app/Service.java
Service#getApplication()ide
public final Application getApplication() {
return mApplication;
}
首先獲取應用程序的Application對象，而後調用Application#getSystemService()。可是，在Application中並無getSystemService()這個方法，那麼這個方法確定在父類中或在某個接口中。追蹤發如今其父類ContextWrapper中。跟進。佈局
源碼位置：frameworks/base/core/java/android/content/ContextWrapper.java
ContextWrapper#getSystemServiceName()動畫
@Override
public String getSystemServiceName(Class<?> serviceClass) {
return mBase.getSystemServiceName(serviceClass);
}
成員變量mBase爲Context對象，跟進。this
源碼位置：frameworks/base/core/java/Android/content/Context.java
Context#getSystemServiceName()
public final <T> T getSystemService(Class<T> serviceClass) {
String serviceName = getSystemServiceName(serviceClass);
return serviceName != null ? (T)getSystemService(serviceName) : null;
}
public abstract Object getSystemService(@ServiceName @NonNull String name);
Context的實現類是ContextImpl，接下來獲取服務的方式和Android XML佈局文件解析過程源碼解析中同樣，爲了節省篇幅，直接進入到SystemServiceRegistry中的靜態代碼快
源碼位置：frameworks/base/core/java/android/app/SystemServiceRegistry.java
static {
...
registerService(Context.WINDOW_SERVICE, WindowManager.class,
new CachedServiceFetcher<WindowManager>() {
@Override
public WindowManager createService(ContextImpl ctx) {
return new WindowManagerImpl(ctx.getDisplay());
}});
...
}
這裏返回了WindowManagerImpl對象，不過最後強轉稱了父類WindowManager。目前爲止，已經獲取到了WindowManager對象，各類參數也已經初始化完成。接下來只有一行WindowManager.addView()。真可謂簡單到極致。極度的簡單每每是繁瑣的假象。接下來，纔是本文真正的開始。
WindowManager.addView()解析
源碼位置：frameworks/base/core/Java/Android/view/WindowManagerImpl.java
WindowManagerImpl#addView()
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyDefaultToken(params);
mGlobal.addView(view, params, mDisplay, mParentWindow);
}
首先驗證Token，這裏不做爲重點。接下來還有個addView()跟進。
源碼位置：frameworks/base/core/Java/Android/view/WindowManagerGlobal.java
WindowManagerGlobal#addView()
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow) {
// 參數效驗
...
ViewRootImpl root;
synchronized (mLock) {
// 查找緩存，類型效驗
...
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
}
try {
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
// who care?
}
}
給咱們的View設置參數並添加到mRoots中，由WindowManagerGlobal進行管理，以後的事情就和View沒什麼關係了。接着調用ViewRootImpl#setView()。跟進。下面是個關鍵點，同窗們注意力要集中。
源碼位置：frameworks/base/core/Java/Android/view/ViewRootImpl.java
ViewRootImpl#setView()
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
synchronized (this) {
// 各類屬性讀取，賦值及效驗
...
try {
...
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(),
mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
mAttachInfo.mOutsets, mInputChannel);
} catch (RemoteException e) {
...
}
mWindowSession是IWindowSession對象。在建立ViewRootImpl對象時被實例化。
public ViewRootImpl(Context context, Display display) {
mWindowSession = WindowManagerGlobal.getWindowSession();
...
}
跟進。
源碼位置：frameworks/base/core/Java/Android/view/WindowManagerGlobal.java
WindowManagerGlobal#getWindowSession()
public static IWindowSession getWindowSession() {
synchronized (WindowManagerGlobal.class) {
if (sWindowSession == null) {
try {
InputMethodManager imm = InputMethodManager.getInstance();
IWindowManager windowManager = getWindowManagerService();
sWindowSession = windowManager.openSession(
new IWindowSessionCallback.Stub() {
@Override
public void onAnimatorScaleChanged(float scale) {
ValueAnimator.setDurationScale(scale);
}
},
imm.getClient(), imm.getInputContext());
} catch (RemoteException e) {
Log.e(TAG, "Failed to open window session", e);
}
}
return sWindowSession;
}
}
這裏getWindowManagerService()經過AIDL返回WindowManagerService實例。以後調用WindowManagerService#openSession()。跟進。
源碼位置：frameworks/base/services/java/com/android/server/wm/WindowManagerService.java
WindowManagerService#getWindowSession()
public IWindowSession openSession(IWindowSessionCallback callback, IInputMethodClient client,
IInputContext inputContext) {
if (client == null) throw new IllegalArgumentException("null client");
if (inputContext == null) throw new IllegalArgumentException("null inputContext");
Session session = new Session(this, callback, client, inputContext);
return session;
}
返回一個Session對象。也就是說在ViewRootImpl#setView()中調用的是Session#addToDisplay()。跟進。
源碼位置：frameworks/base/services/java/com/android/server/wm/Session.java
Session#addToDisplay()
@Override
public int addToDisplay(IWindow window, int seq, WindowManager.LayoutParams attrs,
int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets,
Rect outOutsets, InputChannel outInputChannel) {
return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId,
outContentInsets, outStableInsets, outOutsets, outInputChannel);
}
這裏的mService是個WindowManagerService對象，也就是說最後調用的是WindowManagerService#addWindow()。
源碼位置：frameworks/base/services/java/com/android/server/wm/WindowManagerService.java
WindowManagerService#addWindow()
public int addWindow(...) {
...
WindowState win = new WindowState(this, session, client, token,
attachedWindow, appOp[0], seq, attrs, viewVisibility, displayContent);
win.attach();
mWindowMap.put(client.asBinder(), win);
...
}
mWindowMap是個Map實例，將WindowManager添加進WindowManagerService統一管理。至此，整個添加視圖操做解析完畢。
WindowManager.updateViewLayout()解析
和addView()過程同樣，最終會進入到WindowManagerGlobal#updateViewLayout()。
源碼位置：frameworks/base/core/Java/Android/view/WindowManagerGlobal.java
WindowManagerGlobal#getWindowSession()
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
if (!(params instanceof WindowManager.LayoutParams)) {
throw new IllegalArgumentException("Params must be WindowManager.LayoutParams");
}
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
view.setLayoutParams(wparams);
synchronized (mLock) {
int index = findViewLocked(view, true);
ViewRootImpl root = mRoots.get(index);
mParams.remove(index);
mParams.add(index, wparams);
root.setLayoutParams(wparams, false);
}
將傳入的View設置參數以後，更新mRoot中View的參數。沒撒好說的。next one。
WindowManager.removeView()解析
和上兩個過程同樣，最終會進入到WindowManagerGlobal#removeView()。
public void removeView(View view, boolean immediate) {
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
synchronized (mLock) {
int index = findViewLocked(view, true);
View curView = mRoots.get(index).getView();
removeViewLocked(index, immediate);
if (curView == view) {
return;
}
throw new IllegalStateException("Calling with view " + view
+ " but the ViewAncestor is attached to " + curView);
}
}
private void removeViewLocked(int index, boolean immediate) {
ViewRootImpl root = mRoots.get(index);
View view = root.getView();
...
boolean deferred = root.die(immediate);
if (view != null) {
view.assignParent(null);
if (deferred) {
mDyingViews.add(view);
}
}
}
這個過程要稍微麻煩點，首先調用root.die()，接着將View添加進mDyingViews。跟進。
源碼位置：frameworks/base/core/java/android/view/ViewRootImpl.java
ViewRootImpl#die()
boolean die(boolean immediate) {
...
mHandler.sendEmptyMessage(MSG_DIE);
return true;
}
這裏的參數immediate默認爲false,也就是說這裏只是發送了一個what=MSG_DIE的空消息。ViewRootHandler收到這條消息會執行doDie()。
void doDie() {
checkThread();
...
WindowManagerGlobal.getInstance().doRemoveView(this);
}
跟進。
void doRemoveView(ViewRootImpl root) {
synchronized (mLock) {
final int index = mRoots.indexOf(root);
if (index >= 0) {
mRoots.remove(index);
mParams.remove(index);
final View view = mViews.remove(index);
mDyingViews.remove(view);
}
}
if (HardwareRenderer.sTrimForeground && HardwareRenderer.isAvailable()) {
doTrimForeground();
}
}
通過一圈效驗最終仍是回到WindowManagerGlobal中移除View。
至此，本文已經所有結束，感謝耐心閱讀到最後～
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- 6. Android WindowManager實現懸浮窗效果 (一)——與當前Activity綁定
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- 1. Android懸浮窗實現 使用WindowManager
- 2. Android使用WindowManager實現懸浮窗
- 3. 【轉】android源碼分析之windowmanager (android懸浮窗口的實現)
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- 6. Android WindowManager實現懸浮窗效果 (一)——與當前Activity綁定
- 7. WindowManager和WindowManager.LayoutParams的使用以及實現懸浮窗口的方法
- 8. android 懸浮窗
- 9. Android 相似360懸浮窗口實現源碼
- 10. Android懸浮窗的一種實現