【右滑返回】滑動衝突 Scroller DecorView

時間 2019-11-25

標籤右滑返回滑動衝突 scroller decorview 简体版

原文原文鏈接

基本思想

咱們的滑動邏輯主要是利用View的scrollBy() 方法, scrollTo()方法和Scroller類來實現的

當手指拖動視圖的時候，咱們監聽手指在屏幕上滑動的距離

利用View的scrollBy() 方法使得View隨着手指的滑動而滑動

而當手指離開屏幕，咱們在根據邏輯使用Scroller類startScroll()方法設置滑動的參數，而後再根據View的scrollTo進行滾動。

對於View的滑動，存在一些Touch事件消費的處理等問題，最主要的就是Activity裏面有一些ListView、 GridView、ScrollView等控件

假如咱們Activity裏面存在ListView、GridView等控件的話，咱們對Activity的最外層佈局進行滾動根本就無效果，由於Touch事件被ListView、GridView等控件消費了，因此Activity的最外層佈局根本得不到Touch事件，也就實現不了Touch邏輯了

爲了解決此Touch事件問題，咱們將OnTouchListener直接設置到ListView、GridView上面，這樣子就避免了Activity的最外層接受不到Touch事件的問題了

核心：一個自定義View

public class SwipeBackLayout extends FrameLayout {

//常量

/**手指向右滑動時的最小【滑動】距離（只有滑動超過此距離才滾動view）*/

public static int X_MIN_DISTANCE_IF_MOVE = 8;

/**手指向右滑動時的最大【起始】距離（防止誤操做，只有從左邊緣滑動纔有效），這個值最好大於上面的值*/

public static int X_MIN_START_DISTANCE = 10;

/**手指向右滑動時的最小【滑動】距離（防止誤操做，只有滑動超過必定距離才關閉）*/

public static int X_MIN_DISTANCE_FROM_LEFT = 90;

/**自動滾動到左側(回到初始位置)消耗的時間*/

public static final int TIME_MOVE_TO_LEFT = 20;

/**自動滾動到右側(關閉應用前)消耗的時間*/

public static final int TIME_MOVE_TO_RIGHT = 200;

//一些能夠設置的成員

/**滑動時左邊緣是否顯示陰影*/

private boolean isShowShadow = true;

/**當touch位置有ViewPager，可是ViewPager不是在item0時，是否攔截【從屏幕邊緣down】的滑動事件*/

private boolean isInterceptWhenTouchViewPagerIfNotFirst = false;

/**滑動時左邊緣添加陰影*/

private Drawable mShadowDrawable = getResources().getDrawable(R.drawable.shadow_left);

//臨時變量

/**是否要finish掉Activity*/

private boolean isFinish;

private Activity mActivity;

/**記錄按下時的觸摸點、移動時的觸摸點在屏幕上的X座標*/

private int downX, touchX;

private Scroller mScroller = new Scroller(getContext());

private List<ViewPager> mViewPagers = new LinkedList<ViewPager>();

public SwipeBackLayout(Context context) {

this(context, null);

}

public SwipeBackLayout(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

public SwipeBackLayout(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

DisplayMetrics metric = new DisplayMetrics();

((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay().getMetrics(metric);

X_MIN_DISTANCE_FROM_LEFT = (int) (metric.widthPixels * 0.2f);//屏幕寬的1/5

//滑動的時候，手的移動大於這個距離纔開始移動控件；若是小於這個距離就不觸發移動控件。ViewPage就是用這個距離來判斷用戶是否翻頁的

X_MIN_DISTANCE_IF_MOVE = ViewConfiguration.get(context).getScaledTouchSlop();

Log.i("bqt", X_MIN_DISTANCE_FROM_LEFT + "---" + X_MIN_DISTANCE_IF_MOVE);//144-16

X_MIN_START_DISTANCE = X_MIN_DISTANCE_IF_MOVE + 2;//這個值最好大於X_MIN_DISTANCE_IF_MOVE

}

//必須手動調用的方法

public void attachToActivityAndAsRootLayout(Activity activity) {

mActivity = activity;

FrameLayout decorView = (FrameLayout) activity.getWindow().getDecorView();//全部窗口的根View

ViewGroup decorChild = (ViewGroup) decorView.getChildAt(0);//封裝內容區域和ActionBar區域的容器

decorView.removeView(decorChild);

this. addView ( decorChild ) ;

decorView.addView(this);

}

//******************************************************************************************

@Override

public boolean onInterceptTouchEvent(MotionEvent event) {

if (!isInterceptWhenTouchViewPagerIfNotFirst) {

ViewPager mViewPager = getMyTouchViewPager(mViewPagers, event);

//若是存在ViewPager而且ViewPager不是處在第一個Item，咱們才攔截Touch事件，不然不攔截（Touch事件由ViewPager處理）

if (mViewPager != null && mViewPager.getCurrentItem() != 0) return super.onInterceptTouchEvent(event);

}

switch (event.getActionMasked()) {

case MotionEvent.ACTION_DOWN:

downX = (int) event.getRawX();//getRawX獲取的是相對父View(也即整個屏幕左上角)的位置座標

touchX = downX;

break;

case MotionEvent.ACTION_MOVE:

if (downX <= X_MIN_START_DISTANCE //不是從屏幕左邊緣開始的不攔截

&& event.getRawX() - downX > X_MIN_DISTANCE_IF_MOVE) return true;//滑動距離過小時暫不攔截

break;

}

return super.onInterceptTouchEvent(event);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

switch (event.getActionMasked()) {

case MotionEvent.ACTION_MOVE:

if (event.getRawX() - downX > X_MIN_DISTANCE_IF_MOVE) scrollBy(touchX - (int) event.getRawX(), 0);//將View中的內容滾動指定距離

touchX = (int) event.getRawX();

break;

case MotionEvent.ACTION_UP:

if (Math.abs(getScrollX()) >= X_MIN_DISTANCE_FROM_LEFT) scrollRightOrLeft(true);//當滑動的距離大於咱們設定的最小距離時，滑到右側

else scrollRightOrLeft(false);//當滑動的距離小於咱們設定的最小距離時，回到起始位置

break;

}

return true;

}

@Override

protected void onLayout(boolean changed, int l, int t, int r, int b) {

super.onLayout(changed, l, t, r, b);

if (changed) getAlLViewPager(mViewPagers, this);//【遞歸】遍歷整個View樹，獲取裏面的ViewPager的集合

}

@Override

protected void dispatchDraw(Canvas canvas) {//調用View.onDraw爲繪製VIew自己，調用dispatchDraw爲繪製本身的孩子

//Called by draw to draw the child views. This may be overridden by derived classes to gain control just before its children are drawn

super.dispatchDraw(canvas);

if (isShowShadow && mShadowDrawable != null) {

int left = getLeft() - mShadowDrawable.getIntrinsicWidth();

int right = left + mShadowDrawable.getIntrinsicWidth();

mShadowDrawable.setBounds(left, getTop(), right, getBottom());

mShadowDrawable.draw(canvas);

}

@Override

public void computeScroll() {

if (mScroller.computeScrollOffset()) {

scrollTo(mScroller.getCurrX(), mScroller.getCurrY());

postInvalidate();

if (mScroller.isFinished() && isFinish) mActivity.finish();

}

//******************************************************************************************

/**

* 【遞歸】遍歷整個View樹，獲取裏面的ViewPager的集合

private void getAlLViewPager(List<ViewPager> mViewPagers, ViewGroup parent) {

int childCount = parent.getChildCount();

for (int i = 0; i < childCount; i++) {

View child = parent.getChildAt(i);

if (child instanceof ViewPager) mViewPagers.add((ViewPager) child);

else if (child instanceof ViewGroup) getAlLViewPager(mViewPagers, (ViewGroup) child);

}

/**

* 返回咱們touch範圍內的那個ViewPager

private ViewPager getMyTouchViewPager(List<ViewPager> mViewPagers, MotionEvent ev) {

if (mViewPagers == null || mViewPagers.size() == 0) return null;

Rect mRect = new Rect();

for (ViewPager viewPager : mViewPagers) {

viewPager.getHitRect(mRect);

if (mRect.contains((int) ev.getX(), (int) ev.getY())) return viewPager;

}

return null;

}

/**

* 滾動出界面或滾動到起始位置

private void scrollRightOrLeft(boolean toRight) {

isFinish = toRight;

if (toRight) mScroller.startScroll(getScrollX(), 0, -getWidth() - getScrollX(), 0, TIME_MOVE_TO_RIGHT);

else mScroller.startScroll(getScrollX(), 0, -getScrollX(), 0, TIME_MOVE_TO_LEFT);//int startX, int startY, int dx, int dy, int duration

postInvalidate();//刷新界面

}

//get和set方法******************************************************************************************

public boolean isInterceptWhenTouchViewPagerIfNotFirst() {

return isInterceptWhenTouchViewPagerIfNotFirst;

}

public void setInterceptWhenTouchViewPagerIfNotFirst(boolean isInterceptWhenTouchViewPagerIfNotFirst) {

this.isInterceptWhenTouchViewPagerIfNotFirst = isInterceptWhenTouchViewPagerIfNotFirst;

}

public Drawable getmShadowDrawable() {

return mShadowDrawable;

}

public void setmShadowDrawable(Drawable mShadowDrawable) {

this.mShadowDrawable = mShadowDrawable;

}

public boolean isShowShadow() {

return isShowShadow;

}

public void setShowShadow(boolean isShowShadow) {

this.isShowShadow = isShowShadow;

}

Activity基類

/**

* 想要實現向右滑動刪除Activity效果只須要繼承SwipeBackActivity便可

public class SwipeBackActivity extends Activity {

protected SwipeBackLayout rootLayout;

@Override

protected void onCreate(Bundle savedInstanceState) {

requestWindowFeature(Window.FEATURE_NO_TITLE);//能夠放在super.onCreate以後，但必須放在attachToActivityAndAsRootLayout以前

super.onCreate(savedInstanceState);

rootLayout = new SwipeBackLayout(this);

rootLayout.attachToActivityAndAsRootLayout(this);

}

@Override

public void startActivity(Intent intent) {

super.startActivity(intent);

overridePendingTransition(R.anim.base_slide_right_in, R.anim.base_slide_remain);

}

@Override

public void onBackPressed() {

super.onBackPressed();

overridePendingTransition(0, R.anim.base_slide_right_out);

}

@Override

public void finish() {

super.finish();

overridePendingTransition(0, R.anim.base_slide_right_out);

}

MainActivity

public class MainActivity extends ListActivity {

protected void onCreate(Bundle savedInstanceState) {

requestWindowFeature(Window.FEATURE_NO_TITLE);

super.onCreate(savedInstanceState);

String[] array = { "普通的Activity", //

"普通的Activity：不顯示陰影",//

"普通的Activity：自定義陰影", //

"普通的Activity：背景透明",//

"普通的Activity：Translucent主題",//

"普通的Activity：Holo_Light主題",//

"有ListView的Activity", //

"當touch位置有ViewPager，但ViewPager不是在item0時，不攔截滑動事件",//

"當touch位置有ViewPager，即便ViewPager不是在item0時，也攔截【從屏幕邊緣down】的滑動事件" };//我感受這種方式的用戶體驗更好

setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, new ArrayList<String>(Arrays.asList(array))));

}

@Override

protected void onListItemClick(ListView l, View v, int position, long id) {

if (position <= 5) {

Intent intent = new Intent(this, NormalActivity.class);

intent.putExtra("position", position);

startActivity(intent);

} else if (position == 6) startActivity(new Intent(MainActivity.this, ListViewActivity.class));

else {

Intent intent = new Intent(this, ViewPagerActivity.class);

intent.putExtra("position", position);

startActivity(intent);

}

overridePendingTransition(R.anim.base_slide_right_in, R.anim.base_slide_remain);

}

NormalActivity

public class NormalActivity extends SwipeBackActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

//若是子類要requestWindowFeature，必須放在super.onCreate以前，由於父類SwipeBackActivity的onCreate方法已經獲取到了DecorView

//也即子類在調用super.onCreate後，其窗口裝飾風格(即相應的根佈局文件)已經肯定好了(默認的)，如：是否有標題、是否有icon等。

//因爲要求窗口裝飾風格一經肯定就不能再修改，不然直接拋異常！而requestWindowFeature的做用就是根據你的設置選擇匹配的窗口裝飾風格

//因此requestWindowFeature必須在包括setContentView以及getWindow().getDecorView()等行爲以前調用！

//注意：以上規則只適合requestWindowFeature等方法，全屏設置能夠放在【任何】位置，好比在點擊某個View後調用也是能夠的

requestWindowFeature(Window.FEATURE_LEFT_ICON);//實際上這行代碼沒任何意義，由於會被super.onCreate中的設置覆蓋掉

super.onCreate(savedInstanceState);

TextView tv_info = new TextView(this);

tv_info.setTextColor(Color.BLACK);

tv_info.setTextSize(TypedValue.COMPLEX_UNIT_SP, 25);

tv_info.setBackgroundColor(Color.RED);//必須設置背景色，不然是透明的

tv_info.setGravity(Gravity.CENTER);

switch (getIntent().getIntExtra("position", 0)) {

case 0:

tv_info.setText("默認顯示指定的陰影\n對於普通的Activity，沒必要必定要在屏幕邊緣開始滑才能退出");

break;

case 1:

tv_info.setText("不顯示陰影");

rootLayout.setShowShadow(false);

break;

case 2:

tv_info.setText("自定義陰影");

rootLayout.setmShadowDrawable(getResources().getDrawable(R.drawable.ic_launcher));

break;

case 3:

tv_info.setText("背景透明");

tv_info.setBackgroundColor(Color.TRANSPARENT);

break;

case 4:

tv_info.setText("Translucent主題");

new AlertDialog.Builder(this).setTitle("Translucent主題").create().show();

break;

case 5:

tv_info.setText("Holo_Light主題");

setTheme(android.R.style.Theme_Holo_Light);

new AlertDialog.Builder(this).setTitle("Holo_Light主題").create().show();

break;

}

setContentView(tv_info);

}

ListViewActivity

public class ListViewActivity extends SwipeBackActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

List<String> list = new ArrayList<String>();

for (int i = 0; i <= 30; i++) {

list.add("包含ListView時不會有手勢衝突");

}

ListView mListView = new ListView(this);

mListView.setBackgroundColor(Color.GREEN);//設置背景色

mListView.setAdapter(new ArrayAdapter<String>(ListViewActivity.this, android.R.layout.simple_list_item_1, list));

setContentView(mListView);

}

ViewPagerActivity

public class ViewPagerActivity extends SwipeBackActivity {

private List<View> list = new ArrayList<View>();

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

ViewPager viewPager = new ViewPager(this);

for (int i = 0; i < 5; i++) {

TextView tv_info = new TextView(this);

tv_info.setTextColor(Color.RED);

tv_info.setTextSize(TypedValue.COMPLEX_UNIT_SP, 300);

tv_info.setBackgroundColor(Color.GREEN);//必須設置背景色，不然是透明的

tv_info.setGravity(Gravity.CENTER);

tv_info.setText("" + i);

list.add(tv_info);

}

viewPager.setAdapter(new Adapter(this, list));

setContentView(viewPager);

if (getIntent().getIntExtra("position", 0) == 8) rootLayout.setInterceptWhenTouchViewPagerIfNotFirst(true);

}

public class Adapter extends PagerAdapter {

private List<View> list;

public Adapter(Context context, List<View> list) {

this.list = list;

}

@Override

public int getCount() {

return list.size();

}

@Override

public boolean isViewFromObject(View arg0, Object arg1) {

return arg0 == arg1;

}

@Override

public void destroyItem(ViewGroup container, int position, Object object) {

container.removeView(list.get(position));

}

@Override

public Object instantiateItem(ViewGroup container, int position) {

View v = list.get(position);

container.addView(v);

return v;

}

清單文件

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.example.slidingfinish"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="17"

android:targetSdkVersion="19" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@android:style/Theme.Translucent" >

<activity

android:name=".MainActivity"

android:label="@string/app_name"

android:theme="@android:style/Theme.Holo.Light" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

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