【右滑返回】滑动冲突 Scroller DecorView

基本思想

我们的滑动逻辑主要是利用View的scrollBy() 方法, scrollTo()方法和Scroller类来实现的

当手指拖动视图的时候，我们监听手指在屏幕上滑动的距离

利用View的scrollBy() 方法使得View随着手指的滑动而滑动

而当手指离开屏幕，我们在根据逻辑使用Scroller类startScroll()方法设置滑动的参数，然后再根据View的scrollTo进行滚动。

对于View的滑动，存在一些Touch事件消费的处理等问题，最主要的就是Activity里面有一些ListView、 GridView、ScrollView等控件

假如我们Activity里面存在ListView、GridView等控件的话，我们对Activity的最外层布局进行滚动根本就无效果，因为Touch事件被ListView、GridView等控件消费了，所以Activity的最外层布局根本得不到Touch事件，也就实现不了Touch逻辑了

为了解决此Touch事件问题，我们将OnTouchListener直接设置到ListView、GridView上面，这样子就避免了Activity的最外层接受不到Touch事件的问题了

核心：一个自定义View

public class SwipeBackLayout extends FrameLayout {

//常量

/**手指向右滑动时的最小【滑动】距离（只有滑动超过此距离才滚动view）*/

public static int X_MIN_DISTANCE_IF_MOVE = 8;

/**手指向右滑动时的最大【起始】距离（防止误操作，只有从左边缘滑动才有效），这个值最好大于上面的值*/

public static int X_MIN_START_DISTANCE = 10;

/**手指向右滑动时的最小【滑动】距离（防止误操作，只有滑动超过一定距离才关闭）*/

public static int X_MIN_DISTANCE_FROM_LEFT = 90;

/**自动滚动到左侧(回到初始位置)消耗的时间*/

public static final int TIME_MOVE_TO_LEFT = 20;

/**自动滚动到右侧(关闭应用前)消耗的时间*/

public static final int TIME_MOVE_TO_RIGHT = 200;

//一些可以设置的成员

/**滑动时左边缘是否显示阴影*/

private boolean isShowShadow = true;

/**当touch位置有ViewPager，但是ViewPager不是在item0时，是否拦截【从屏幕边缘down】的滑动事件*/

private boolean isInterceptWhenTouchViewPagerIfNotFirst = false;

/**滑动时左边缘添加阴影*/

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

//临时变量

/**是否要finish掉Activity*/

private boolean isFinish;

private Activity mActivity;

/**记录按下时的触摸点、移动时的触摸点在屏幕上的X坐标*/

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);//屏幕宽的1/5

//滑动的时候，手的移动大于这个距离才开始移动控件；如果小于这个距离就不触发移动控件。ViewPage就是用这个距离来判断用户是否翻页的

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;//这个值最好大于X_MIN_DISTANCE_IF_MOVE

}

//必须手动调用的方法

public void attachToActivityAndAsRootLayout(Activity activity) {

mActivity = activity;

FrameLayout decorView = (FrameLayout) activity.getWindow().getDecorView();//所有窗口的根View

ViewGroup decorChild = (ViewGroup) decorView.getChildAt(0);//封装内容区域和ActionBar区域的容器

decorView.removeView(decorChild);

this.addView(decorChild);

decorView.addView(this);

}

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

@Override

public boolean onInterceptTouchEvent(MotionEvent event) {

if (!isInterceptWhenTouchViewPagerIfNotFirst) {

ViewPager mViewPager = getMyTouchViewPager(mViewPagers, event);

//如果存在ViewPager并且ViewPager不是处在第一个Item，我们才拦截Touch事件，否则不拦截（Touch事件由ViewPager处理）

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

}

switch (event.getActionMasked()) {

case MotionEvent.ACTION_DOWN:

downX = (int) event.getRawX();//getRawX获取的是相对父View(也即整个屏幕左上角)的位置坐标

touchX = downX;

break;

case MotionEvent.ACTION_MOVE:

if (downX <= X_MIN_START_DISTANCE //不是从屏幕左边缘开始的不拦截

&& event.getRawX() - downX > X_MIN_DISTANCE_IF_MOVE) return true;//滑动距离太小时暂不拦截

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);//将View中的内容滚动指定距离

touchX = (int) event.getRawX();

break;

case MotionEvent.ACTION_UP:

if (Math.abs(getScrollX()) >= X_MIN_DISTANCE_FROM_LEFT) scrollRightOrLeft(true);//当滑动的距离大于我们设定的最小距离时，滑到右侧

else scrollRightOrLeft(false);//当滑动的距离小于我们设定的最小距离时，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);//【递归】遍历整个View树，获取里面的ViewPager的集合

}

@Override

protected void dispatchDraw(Canvas canvas) {//调用View.onDraw为绘制VIew本身，调用dispatchDraw为绘制自己的孩子

//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();

}

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

/**

* 【递归】遍历整个View树，获取里面的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);

}

/**

* 返回我们touch范围内的那个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;

}

/**

* 滚动出界面或滚动到起始位置

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基类

/**

* 想要实现向右滑动删除Activity效果只需要继承SwipeBackActivity即可

public class SwipeBackActivity extends Activity {

protected SwipeBackLayout rootLayout;

@Override

protected void onCreate(Bundle savedInstanceState) {

requestWindowFeature(Window.FEATURE_NO_TITLE);//可以放在super.onCreate之后，但必须放在attachToActivityAndAsRootLayout之前

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：不显示阴影",//

"普通的Activity：自定义阴影", //

"普通的Activity：背景透明",//

"普通的Activity：Translucent主题",//

"普通的Activity：Holo_Light主题",//

"有ListView的Activity", //

"当touch位置有ViewPager，但ViewPager不是在item0时，不拦截滑动事件",//

"当touch位置有ViewPager，即使ViewPager不是在item0时，也拦截【从屏幕边缘down】的滑动事件" };//我感觉这种方式的用户体验更好

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) {

//如果子类要requestWindowFeature，必须放在super.onCreate之前，因为父类SwipeBackActivity的onCreate方法已经获取到了DecorView

//也即子类在调用super.onCreate后，其窗口装饰风格(即相应的根布局文件)已经确定好了(默认的)，如：是否有标题、是否有icon等。

//由于要求窗口装饰风格一经确定就不能再修改，否则直接抛异常！而requestWindowFeature的作用就是根据你的设置选择匹配的窗口装饰风格

//所以requestWindowFeature必须在包括setContentView以及getWindow().getDecorView()等行为之前调用！

//注意：以上规则只适合requestWindowFeature等方法，全屏设置可以放在【任何】位置，比如在点击某个View后调用也是可以的

requestWindowFeature(Window.FEATURE_LEFT_ICON);//实际上这行代码没任何意义，因为会被super.onCreate中的设置覆盖掉

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);//必须设置背景色，否则是透明的

tv_info.setGravity(Gravity.CENTER);

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

case 0:

tv_info.setText("默认显示指定的阴影\n对于普通的Activity，不必一定要在屏幕边缘开始滑才能退出");

break;

case 1:

tv_info.setText("不显示阴影");

rootLayout.setShowShadow(false);

break;

case 2:

tv_info.setText("自定义阴影");

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主题");

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

break;

case 5:

tv_info.setText("Holo_Light主题");

setTheme(android.R.style.Theme_Holo_Light);

new AlertDialog.Builder(this).setTitle("Holo_Light主题").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时不会有手势冲突");

}

ListView mListView = new ListView(this);

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

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);//必须设置背景色，否则是透明的

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;

}

清单文件

<?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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