仿QQ侧滑删除，自定义ListView

废话不多说，直接代码

1.自定义QQListView:

public class QQListView extends ListView {

private int mScreenWidth;   // 屏幕宽度
private int mDownX;         // 按下点的x值
private int mDownY;         // 按下点的y值
private int mDeleteBtnWidth;     // 删除按钮的宽度

private boolean isDeleteShown;  // 删除按钮是否正在显示

private ViewGroup mPointChild;  // 当前处理的item
private LinearLayout.LayoutParams mLayoutParams;   // 当前处理的item的LayoutParams

public QQListView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}

public QQListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);

// 获取屏幕宽度
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
mScreenWidth = dm.widthPixels;
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
performActionDown(ev);
break;
case MotionEvent.ACTION_MOVE:
return performActionMove(ev);
case MotionEvent.ACTION_UP:
performActionUp();
break;
}

return super.onTouchEvent(ev);
}

// 处理action_down事件
private void performActionDown(MotionEvent ev) {
if(isDeleteShown) {
turnToNormal();
}

mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
// 获取当前点的item
mPointChild = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY)
- getFirstVisiblePosition());
// 获取删除按钮的宽度
mDeleteBtnWidth = mPointChild.getChildAt(1).getLayoutParams().width;
mLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0)
.getLayoutParams();
// 为什么要重新设置layout_width 等于屏幕宽度
// 因为match_parent时，不管你怎么滑，都不会显示删除按钮
// why？ 因为match_parent时，ViewGroup就不去布局剩下的view
mLayoutParams.width = mScreenWidth;
mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
}

// 处理action_move事件
private boolean performActionMove(MotionEvent ev) {
int nowX = (int) ev.getX();
int nowY = (int) ev.getY();
if(Math.abs(nowX - mDownX) > Math.abs(nowY - mDownY)) {
// 如果向左滑动
if(nowX < mDownX) {
// 计算要偏移的距离
int scroll = (nowX - mDownX) / 2;
// 如果大于了删除按钮的宽度， 则最大为删除按钮的宽度
if(-scroll >= mDeleteBtnWidth) {
scroll = -mDeleteBtnWidth;
}
// 重新设置leftMargin
mLayoutParams.leftMargin = scroll;
mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
}

return true;
}
return super.onTouchEvent(ev);
}

// 处理action_up事件
private void performActionUp() {
// 偏移量大于button的一半，则显示button
// 否则恢复默认
if(-mLayoutParams.leftMargin >= mDeleteBtnWidth / 2) {
mLayoutParams.leftMargin = -mDeleteBtnWidth;
isDeleteShown = true;
}else {
turnToNormal();
}

mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
}

/**
* 变为正常状态
*/
public void turnToNormal() {
mLayoutParams.leftMargin = 0;
mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
isDeleteShown = false;
}

/**
* 当前是否可点击
* @return 是否可点击
*/
public boolean canClick() {
return !isDeleteShown;
}
}

2.在activity_main.xml文件中声明QQListView而不是ListView了：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}" >

<com.example.qqdelete.QQListView
android:id="@+id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:cacheColorHint="@android:color/transparent"
android:listSelector="@android:color/transparent"
android:divider="@android:color/darker_gray"
android:dividerHeight="2dp" />

</RelativeLayout>

3.给QQListView准备好Item_layout布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >

<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="20dp"
android:paddingLeft="10dp"
android:paddingTop="20dp"
android:background="@android:color/white"/>

<TextView
android:id="@+id/delete"
android:layout_width="80dp"
android:layout_height="match_parent"
android:background="#FFFF0000"
android:gravity="center"
android:paddingLeft="20dp"
android:textColor="@android:color/white"
android:paddingRight="20dp"
android:text="删除" />

</LinearLayout>

4.在MainActivity中给 QQListView设置适配器：

public class MainActivity extends Activity {

private QQListView mListView;
private ArrayList<String> mData = new ArrayList<String>() {
{
for(int i=0;i<50;i++) {
add("hello world, hello android  " + i);
}
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

mListView = (QQListView) findViewById(R.id.list);
mListView.setAdapter(new MyAdapter());
mListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if(mListView.canClick()) {
Toast.makeText(MainActivity.this, mData.get(position), Toast.LENGTH_SHORT).show();
}
}
});
}

class MyAdapter extends BaseAdapter {

@Override
public int getCount() {
return mData.size();
}

@Override
public Object getItem(int position) {
return mData.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
if(null == convertView) {
convertView = View.inflate(MainActivity.this, R.layout.item_layout, null);
}
TextView tv = (TextView) convertView.findViewById(R.id.tv);
TextView delete = (TextView) convertView.findViewById(R.id.delete);

tv.setText(mData.get(position));

final int pos = position;
delete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mData.remove(pos);
notifyDataSetChanged();
mListView.turnToNormal();
}
});

return convertView;
}
}
}

QQ侧滑就是如此SO easy，完结