Android 之自定義佈局（繼承控制元件）
阿新 • • 發佈：2019-01-12
就是繼承已有的控制元件，建立新控制元件，保留繼承的父控制元件的特性，並且還可以引入新特性。下面就以支援橫向滑動刪除列表項的自定義ListView的實現來介紹。
1、建立刪除按鈕佈局delete_btn.xml，這個佈局是在橫向滑動列表項後顯示的：
以上程式碼實現le，自定義View。重點：在重寫ListView 時，在類中進行復雜操作。比如點選事件，觸控事件，顯示佈局，更新佈局。在此進行相關的操作～（佈局的變化）然後可以寫一些介面，可供使用的類呼叫！
1、建立刪除按鈕佈局delete_btn.xml，這個佈局是在橫向滑動列表項後顯示的：
<?xml version="1.0" encoding="utf-8"?>
<Button xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#FF0000"
android:padding="5dp"
android:text="\u5220\u9664"
android:textColor="#FFFFFF"
android:textSize="16sp" >
</Button> 2、建立CustomListView類，繼承自ListView，並實現了OnTouchListener和OnGestureListener介面：
package cn.com.tcl.customlistview;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.RelativeLayout;
public class CustomListViewActivity extends ListView implements View.OnTouchListener, GestureDetector.OnGestureListener {
private final GestureDetector mGestureDetector;
private View mDeletBtn;
private ViewGroup mItemLAyout;
private int mSelecteditem,mlastSelecteditem;
private boolean isDelectShown;
private OnDeleteListener mOnDeleteListener;
public interface OnDeleteListener {
void onDelete(int index);
}
public CustomListViewActivity(Context context, AttributeSet attrs) {
super(context, attrs);
mGestureDetector = new GestureDetector(getContext(), this);
setOnTouchListener(this);
}
public void setOnDeleteListener(OnDeleteListener listener) {
mOnDeleteListener = listener;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if (isDelectShown) {
Log.d("haha", "onTouch:---isDelectShown ");
hideDelete();
return false;
} else {
return mGestureDetector.onTouchEvent(event);
}
}
@Override
public boolean onDown(MotionEvent e) {
if(!isDelectShown){
mSelecteditem = pointToPosition((int) e.getX(),(int) e.getY());
mlastSelecteditem = mSelecteditem;
Log.d("haha", "onDown: --->mSelecteditem:"+mSelecteditem);
}
return false;
}
@Override
public void onShowPress(MotionEvent e) {
Log.d("haha", "onShowPress: ");
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
Log.d("haha", "onSingleTapUp: ");
return false;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
// Log.d("haha", "onScroll: ");
return false;
}
@Override
public void onLongPress(MotionEvent e) {
Log.d("haha", "onLongPress: ");
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
mSelecteditem = pointToPosition((int) e2.getX(),(int) e2.getY());
Log.d("haha", "onFling: --->mSelecteditem:"+mSelecteditem);
if(mlastSelecteditem != mSelecteditem && isDelectShown){
hideDelete();
}
if (!isDelectShown && Math.abs(velocityX) > Math.abs(velocityY)) {
mDeletBtn = LayoutInflater.from(getContext()).inflate(R.layout.delect_btn, null);
mDeletBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mItemLAyout.removeView(mDeletBtn);
mDeletBtn = null;
isDelectShown = false;
Log.d("haha", "onClick:--> delete"+mSelecteditem);
mOnDeleteListener.onDelete(mSelecteditem);
}
});
mItemLAyout = (ViewGroup) getChildAt(mSelecteditem - getFirstVisiblePosition());
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
params.addRule(RelativeLayout.CENTER_VERTICAL);
mItemLAyout.addView(mDeletBtn, params);
isDelectShown = true;
}
return false;
}
void hideDelete(){
mItemLAyout.removeView(mDeletBtn);
mDeletBtn = null;
isDelectShown = false;
}
public boolean isDelectShown() {
return isDelectShown;
}
} <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:descendantFocusability="blocksDescendants" >
<TextView
android:id="@+id/content_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_margin="30dp"
android:gravity="center_vertical|left" />
</RelativeLayout>
</LinearLayout> public class CustomListViewAdapter extends ArrayAdapter<String> {
public CustomListViewAdapter(Context context, int textViewResourceId,
List<String> objects) {
super(context, textViewResourceId, objects);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
if (convertView == null) {
view = LayoutInflater.from(getContext()).inflate(
R.layout.custom_listview_item, null);
} else {
view = convertView;
}
TextView contentTv = (TextView) view.findViewById(R.id.content_tv);
contentTv.setText(getItem(position));
return view;
}
}<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<com.example.test.CustomListView
android:id="@+id/custom_lv"
android:layout_width="match_parent"
android:layout_height="wrap_content" />public class MainActivity extends Activity {
// 自定義Lv
private CustomListView mCustomLv;
// 自定義介面卡
private CustomListViewAdapter mAdapter;
// 內容列表
private List<String> contentList = new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
initContentList();
mCustomLv = (CustomListView) findViewById(R.id.custom_lv);
mCustomLv.setOnDeleteListener(new OnDeleteListener() {
@Override
public void onDelete(int index) {
contentList.remove(index);
mAdapter.notifyDataSetChanged();
}
});
mAdapter = new CustomListViewAdapter(this, 0, contentList);
mCustomLv.setAdapter(mAdapter);
}
// 初始化內容列表
private void initContentList() {
for (int i = 0; i < 20; i++) {
contentList.add("內容項" + i);
}
}
@Override
public void onBackPressed() {
if (mCustomLv.isDeleteShown()) {
mCustomLv.hideDelete();
return;
}
super.onBackPressed();
}
}以上程式碼實現le，自定義View。重點：在重寫ListView 時，在類中進行復雜操作。比如點選事件，觸控事件，顯示佈局，更新佈局。在此進行相關的操作～（佈局的變化）然後可以寫一些介面，可供使用的類呼叫！