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

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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. [email protected]
   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. [email protected]
   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。

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   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. [email protected]
   11. ????public
       void onCreate(Bundle savedInstanceState) {
   12. ????????super.onCreate(savedInstanceState);
   13. ????????setContentView(R.layout.main);
   14. ????}
   15. }

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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. [email protected]
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。

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1. 继承控件

   截图：

   

   程序结构：

   

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   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

   

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   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. [email protected]
   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. [email protected]
   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. [email protected]
   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. [email protected]
   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. [email protected]
   99. ????public
       void onShowPress(MotionEvent motionEvent) {
   100. ?
   101. ????}
   102. ?
   103. [email protected]
   104. ????public
        boolean onSingleTapUp(MotionEvent motionEvent) {
   105. ????????return
        false;
   106. ????}
   107. ?
   108. [email protected]
   109. ????public
        boolean onScroll(MotionEvent motionEvent, MotionEvent motionEvent1, float v, float v1) {
   110. ????????return
        false;
   111. ????}
   112. ?
   113. [email protected]
   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。

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   ?

   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

   

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   ?

   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. [email protected]
   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。

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   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

   

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   ?

   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. [email protected]
   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. [email protected]
   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. }