深入了解view以及自定义控件

参考文章： http://blog.csdn.net/guolin_blog/article/details/12921889
Android LayoutInflater原理分析，带你一步步深入了解View(一)
Android自定义View的实现方法，带你一步步深入了解View(四)

这里面总共有三种自定义控件：

自绘控件、组合控件、继承控件

 

1. 自绘控件
   1. package com.example.DefineView1;
   2.  
   3. import android.content.Context;
   4. import android.graphics.Canvas;
   5. import android.graphics.Color;
   6. import android.graphics.Paint;
   7. import android.graphics.Rect;
   8. import android.util.AttributeSet;
   9. import android.view.View;
   10.  
   11. /**
   12.  * Created by zhuxuekui on 2015/5/18.
   13.  */
   14.  
   15. /**
   16.  * 自定义组合控件之 自绘控件
   17.  */
   18. public
       class CounterView extends View implements View.OnClickListener {
   19.  
   20.     private Paint mPaint;
   21.     private Rect mBounds;
   22.     private
       int mCount;
   23.     public CounterView(Context context, AttributeSet attrs) {
   24.         super(context, attrs);
   25.         mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
   26.         mBounds = new Rect();
   27.         setOnClickListener(this);
   28.  
   29.     }
   30.  
   31.     @Override
   32.     protected
       void onDraw(Canvas canvas) {
   33.         super.onDraw(canvas);
   34.         mPaint.setColor(Color.BLUE);
   35.         canvas.drawRect(0, 0, getWidth(), getHeight(), mPaint);
   36.         mPaint.setColor(Color.YELLOW);
   37.         mPaint.setTextSize(30);
   38.         String text = String.valueOf(mCount);
   39.         mPaint.getTextBounds(text,0,text.length(),mBounds);// 获取文字区域（其实是一个mBounds）的宽度与高度，然后回调。
   40.         float textWidth = mBounds.width();
   41.         float textHeight = mBounds.height();
   42.         canvas.drawText(text, getWidth() / 2 - textWidth / 2, getHeight() / 2
   43.                 + textHeight / 2, mPaint); //在画布上绘制文字
   44.     }
   45.  
   46.     @Override
   47.     public
       void onClick(View view) {
   48.           mCount++;
   49.           invalidate(); //重绘
   50.     }
   51. }

   在CounterView中，我们先初始化一些数据，然后设置view的点击事件。然后调用onclick方法，这里面有invalidate方法，重绘命令。然后调用ondraw方法，开始进行视图的绘制。

    

   

   1. package com.example.DefineView1;
   2.  
   3. import android.app.Activity;
   4. import android.os.Bundle;
   5.  
   6. public
      class MyActivity extends Activity {
   7.     /**
   8.      * Called when the activity is first created.
   9.      */
   10.     @Override
   11.     public
       void onCreate(Bundle savedInstanceState) {
   12.         super.onCreate(savedInstanceState);
   13.         setContentView(R.layout.main);
   14.     }
   15. }

 

 

1. 组合控件

程序结构：

1. package com.example.DefineView2;
2.  
3. import android.app.Activity;
4. import android.content.Context;
5. import android.util.AttributeSet;
6. import android.view.LayoutInflater;
7. import android.view.View;
8. import android.widget.Button;
9. import android.widget.FrameLayout;
10. import android.widget.TextView;
11.  
12. /**
13.  * Created by zhuxuekui on 2015/5/18.
14.  */
15. public
    class TitleView extends FrameLayout {
16.  
17.     private Button leftButton;
18.     private TextView titleText;
19.     public TitleView(Context context, AttributeSet attrs) {
20.         super(context, attrs);
21.         LayoutInflater.from(context).inflate(R.layout.title, this);
22.         titleText = (TextView)findViewById(R.id.title_text);
23.         leftButton = (Button)findViewById(R.id.button_left);
24.         leftButton.setOnClickListener(new OnClickListener() {
25.             @Override
26.             public
    void onClick(View view) {
27.                 ((Activity)getContext()).finish();
28.             }
29.         });
30.     }
31.  
32.     public
    void setTitleText(String text)
33.     {
34.         titleText.setText(text);
35.     }
36.  
37.     public
    void setLeftButtonText(String text)
38.     {
39.         leftButton.setText(text);
40.     }
41.  
42.     public
    void setLeftButtonListener(OnClickListener l)
43.     {
44.         leftButton.setOnClickListener(l);
45.     }
46. }

首先我们定义title.xml下面的，然后定义TextView 继承FragmentLayout ,代码如上面的所示。里面我们对xml里面的控件进行初始化，设置事件都可以。

 

 

 

 

1. 继承控件

   截图：

   

   程序结构：

   

    

    

   1）增加的小按钮，只有一个button，没有布局

   Delete_button.xml 子定义的listview里面增加的内容

   

    

   2）编写我们自己的mylistview类

   Mylistview

   1. package com.example.DefineView3;
   2.  
   3. import android.content.Context;
   4. import android.util.AttributeSet;
   5. import android.view.*;
   6. import android.widget.ListView;
   7. import android.widget.RelativeLayout;
   8.  
   9. /**
   10.  * Created by zhuxuekui on 2015/5/18.
   11.  */
   12. public
       class MyListView extends ListView implements View.OnTouchListener,GestureDetector.OnGestureListener {
   13.     private GestureDetector gestureDetector;
   14.     private OnDeleteListener listener;
   15.     private View deleteButton;
   16.     private ViewGroup itemLayout;
   17.     private
       int selectedItem;
   18.     private
       boolean isDeleteShown;
   19.  
   20.     public MyListView(Context context, AttributeSet attrs) {
   21.         super(context, attrs);
   22.         gestureDetector = new GestureDetector(getContext(),this);
   23.         setOnTouchListener(this);
   24.     }
   25.  
   26.     public
       void setOnDeleteListener(OnDeleteListener l)
   27.     {
   28.         listener = l;
   29.     }
   30.  
   31.  
   32.  
   33.  
   34.     @Override
   35.     public
       boolean onTouch(View view, MotionEvent motionEvent) {
   36.         if(isDeleteShown){
   37.             itemLayout.removeView(deleteButton);
   38.             deleteButton = null;
   39.             isDeleteShown = false;
   40.             return
       false;
   41.         }else{
   42.             return gestureDetector.onTouchEvent(motionEvent);
   43.         }
   44.     }
   45.  
   46. //下面几个方法是OnTouchEvent的事件处理
   47.  
   48.     /**
   49.      * 手指按下事件处理
   50.      * @param motionEvent
   51.      * @return
   52.      */
   53.     @Override
   54.     public
       boolean onDown(MotionEvent motionEvent) {
   55.         if(!isDeleteShown)
   56.         {
   57.             selectedItem = pointToPosition((int)motionEvent.getX(),(int)motionEvent.getY());//判断当前选中的是listview的第几行
   58.         }
   59.         return
       false;
   60.     }
   61.  
   62.     /**
   63.      * 快速滑动事件处理
   64.      * @param motionEvent
   65.      * @param motionEvent1
   66.      * @param X
   67.      * @param Y
   68.      * @return
   69.      */
   70.     @Override
   71.     public
       boolean onFling(MotionEvent motionEvent, MotionEvent motionEvent1, float X, float Y) {
   72.  
   73.         // 快速滑动到某一行上，加载布局deleteButton，并将删除按钮添加到当前选中的那一行item中
   74.         if(!isDeleteShown && Math.abs(X) > Math.abs(Y)){
   75.             deleteButton = LayoutInflater.from(getContext()).inflate(R.layout.delete_button,null);
   76.             deleteButton.setOnClickListener(new OnClickListener() {
   77.                 @Override
   78.                 public
       void onClick(View view) {
   79.                     //当点击了删除按钮，我们就去回调onDeleteListener的onDelete()方法
   80.                     itemLayout.removeView(deleteButton);
   81.                     deleteButton = null;
   82.                     isDeleteShown = false;
   83.                     listener.onDelete(selectedItem);
   84.                 }
   85.             });
   86.  
   87.             itemLayout = (ViewGroup)getChildAt(selectedItem - getFirstVisiblePosition());
   88.             RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
   89.             params.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
   90.             params.addRule(RelativeLayout.CENTER_VERTICAL);
   91.             itemLayout.addView(deleteButton, params);
   92.             isDeleteShown = true;
   93.         }
   94.  
   95.         return
       false;
   96.     }
   97.  
   98.     @Override
   99.     public
       void onShowPress(MotionEvent motionEvent) {
   100.  
   101.     }
   102.  
   103.     @Override
   104.     public
        boolean onSingleTapUp(MotionEvent motionEvent) {
   105.         return
        false;
   106.     }
   107.  
   108.     @Override
   109.     public
        boolean onScroll(MotionEvent motionEvent, MotionEvent motionEvent1, float v, float v1) {
   110.         return
        false;
   111.     }
   112.  
   113.     @Override
   114.     public
        void onLongPress(MotionEvent motionEvent) {
   115.  
   116.     }
   117.  
   118.     public
        interface OnDeleteListener{
   119.         void onDelete(int index);
   120.     }
   121. }

   先去执行构造方法，创建gestureDetector手势捕捉监听程序，以及注册了ontouch监听。当我们按下的时候，触屏就算，程序执行到onTouch() 中，如果删除按钮已经显示我们删除掉图标，如果没有显示删除图标，我们使用gestureDetector来处理当前手势。然后我们执行gestureDetector.onTouchEvent(motionEvent) 。这里面包含多个方法，首先是onDown（），捕捉我们的手指按在了哪一行，我们记录下，滑动的时候，执行onfling(),

   当按钮没有显示，然后我们去加载delete_button.xml此布局，然后并将其现在在listview当前选择的那一行上面，当我们点击删除图标的时候，执行回调方法，执行相应的逻辑。这部分逻辑在主界面中完成。

    

    

   3）建立listview里面的子项

   至此，新建上面的mylistview里面的每一个子项，my_list_view_item.xml.

   My_list_view_item.xml listview 的子项

   

    

    

   4）建立适配器类，继承ArrayAdapter

    

   下一步就是新建适配器类

   1. package com.example.DefineView3;
   2.  
   3. import android.content.Context;
   4. import android.view.LayoutInflater;
   5. import android.view.View;
   6. import android.view.ViewGroup;
   7. import android.widget.ArrayAdapter;
   8. import android.widget.TextView;
   9.  
   10. import java.util.List;
   11.  
   12. /**
   13.  * Created by zhuxuekui on 2015/5/18.
   14.  */
   15. public
       class MyAdapter extends ArrayAdapter<String> {
   16.  
   17.     public MyAdapter(Context context, int resource, List<String> objects) {
   18.         super(context, resource, objects);
   19.     }
   20.  
   21.     @Override
   22.     public View getView(int position, View convertView, ViewGroup parent) {
   23.         View view;
   24.         if(convertView == null)
   25.         {
   26.             view = LayoutInflater.from(getContext()).inflate(R.layout.my_list_view_item,null);
   27.         }else{
   28.             view = convertView;
   29.         }
   30.  
   31.         TextView textView = (TextView)view.findViewById(R.id.text_view);
   32.         textView.setText(getItem(position));
   33.         return view;
   34.     }
   35. }

   这一步主要就是重载ArrayAdapter，并重写构造方法和getview方法。

    

   5）编写主界面的布局，使用自定义的listview控件

    

   Mail.xml 布局自定义的listview

   

    

    

   6）写主界面myactivity.java

   1. package com.example.DefineView3;
   2.  
   3. import android.app.Activity;
   4. import android.os.Bundle;
   5.  
   6. import java.util.ArrayList;
   7. import java.util.List;
   8.  
   9.  
   10. /**
   11.  * 自定义控件3 之 继承控件
   12.  */
   13. public
       class MyActivity extends Activity {
   14.  
   15.     private MyListView myListView;
   16.     private MyAdapter adapter;
   17.     private List<String> contentList = new ArrayList<String>();
   18.  
   19.     /**
   20.      * Called when the activity is first created.
   21.      */
   22.     @Override
   23.     public
       void onCreate(Bundle savedInstanceState) {
   24.         super.onCreate(savedInstanceState);
   25.         setContentView(R.layout.main);
   26.         initList();
   27.         myListView = (MyListView)findViewById(R.id.my_list_view);
   28.         myListView.setOnDeleteListener(new MyListView.OnDeleteListener() {
   29.             @Override
   30.             public
       void onDelete(int index) {
   31.                 contentList.remove(index);
   32.                 adapter.notifyDataSetChanged();
   33.             }
   34.         });
   35.  
   36.         adapter = new MyAdapter(this,0,contentList);
   37.         myListView.setAdapter(adapter);
   38.     }
   39.  
   40.     private
       void initList(){
   41.         contentList.add("Content Item 1");
   42.         contentList.add("Content Item 2");
   43.         contentList.add("Content Item 3");
   44.         contentList.add("Content Item 4");
   45.         contentList.add("Content Item 5");
   46.         contentList.add("Content Item 6");
   47.         contentList.add("Content Item 7");
   48.         contentList.add("Content Item 8");
   49.         contentList.add("Content Item 9");
   50.         contentList.add("Content Item 10");
   51.         contentList.add("Content Item 11");
   52.         contentList.add("Content Item 12");
   53.         contentList.add("Content Item 13");
   54.         contentList.add("Content Item 14");
   55.         contentList.add("Content Item 15");
   56.         contentList.add("Content Item 16");
   57.         contentList.add("Content Item 17");
   58.         contentList.add("Content Item 18");
   59.         contentList.add("Content Item 19");
   60.         contentList.add("Content Item 20");
   61.     }
   62. }