Android自定义控件之电话拨打小键盘

关于Android的自定义控件，之前也写了两个，一个是简单地继承View，另一个通过继承Layout实现一个省市联动控件。这篇，将通过继承ViewGroup来实现一个电话拨打小键盘。本人一贯风格，懒得罗里吧嗦讲一大堆，直接上图上代码，一切尽在注释中！

1、MyPhoneCard.java

/** 
 * 
 * 自定义一个4*3的拨打电话的布局控件, 
 * 
 * 
 */ 
public class MyPhoneCard extends ViewGroup{ 
   
  private static final int COLUMNS = 3; 
  private static final int ROWS = 4; 
  private static final int NUM_BUTTON = COLUMNS*ROWS; 
   
  private View[] mButtons = new View[NUM_BUTTON]; 
   
  private int mButtonWidth; 
  private int mButtonHeight; 
  private int mPaddingLeft; 
  private int mPaddingRight; 
  private int mPaddingTop; 
  private int mPaddingBottom; 
  private int mWidthInc; 
  private int mHeightInc; 
  private int mWidth; 
  private int mHeight; 
 
  public MyPhoneCard(Context context) { 
    super(context); 
  } 
   
  public MyPhoneCard(Context context, AttributeSet attrs){ 
    super(context,attrs); 
  } 
   
  public MyPhoneCard(Context context, AttributeSet attrs, int defStyle){ 
    super(context,attrs,defStyle); 
  } 
   
  /** 
   * 当从xml将所有的控件都调入内存后，触发的动作 
   * 在这里获取控件的大小，并计算整个ViewGroup需要的总的宽和高 
   */ 
  @Override 
  protected void onFinishInflate(){ 
    super.onFinishInflate(); 
    final View[] btns = mButtons; 
     
    for(int i=0; i<NUM_BUTTON; i++){ 
      btns[i] = this.getChildAt(i); 
      btns[i].measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED); 
    } 
     
    //缓存大小 
    final View child = btns[0]; 
    mButtonWidth = child.getMeasuredWidth(); 
    mButtonHeight = child.getMeasuredHeight(); 
    mPaddingLeft = this.getPaddingLeft(); 
    mPaddingRight = this.getPaddingRight(); 
    mPaddingTop = this.getPaddingTop(); 
    mPaddingBottom = this.getPaddingBottom(); 
    mWidthInc = mButtonWidth + mPaddingLeft + mPaddingRight; 
    mHeightInc = mButtonHeight + mPaddingTop + mPaddingBottom; 
     
    mWidth = mWidthInc*COLUMNS; 
    mHeight = mHeightInc*ROWS; 
     
    Log.v("Finish Inflate:", "btnWidth="+mButtonWidth+",btnHeight="+mButtonHeight+",padding:"+mPaddingLeft+","+mPaddingTop+","+mPaddingRight+","+mPaddingBottom); 
 
     
     
  } 
   
  /** 
   * 这个方法在onFinishInflate之后，onLayout之前调用。这个方面调用两次 
   */ 
  @Override 
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){ 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
    Log.v("ViewGroup SIZE：width=", mWidth+""); 
    Log.v("ViewGroup SIZE: height=",mHeight+""); 
    final int width = resolveSize(mWidth, widthMeasureSpec);//传入我们希望得到的宽度，得到测量后的宽度 
    final int height = resolveSize(mHeight,heightMeasureSpec);//传入我们希望得到的高度，得到测量后的高度 
    Log.v("ViewGroup Measured SIZE: width=", width+""); 
    Log.v("ViewGroup Measured SIZE: height=", height+""); 
    //重新计算后的结果，需要设置。下面这个方法必须调用 
    setMeasuredDimension(width, height); 
  } 
 
  /** 
   * 这个方法在onMeasure之后执行，这个自定义控件中含有12个子控件（每个小键），所以，重写这个方法， 
   * 调用每个键的layout，将他们一个一个布局好 
   * 就是4*3的放置，很简单，一个嵌套循环搞定 
   */ 
  @Override 
  protected void onLayout(boolean changed, int left, int top, int right, int bottom) { 
    final View[] buttons = mButtons; 
    int i = 0; 
    Log.v("BOTTOM:", bottom+""); 
    Log.v("TOP", top+""); 
     
    int y = (bottom - top) - mHeight + mPaddingTop;//这里其实bottom-top=mHeight,所以y=mPaddingTop 
    Log.v("Y=", y+""); 
    for(int row=0; row<ROWS; row++){ 
      int x = mPaddingLeft; 
      for(int col = 0; col < COLUMNS; col++){ 
        buttons[i].layout(x, y, x+mButtonWidth, y+mButtonHeight); 
        x = x + mWidthInc; 
        i++; 
      } 
      y = y + mHeightInc; 
    } 
  } 
 
} 

2、布局文件：

<?xml version="1.0" encoding="utf-8"?> 
<demo.phone.card.MyPhoneCard 
 xmlns:android="http://schemas.android.com/apk/res/android"  
 android:id = "@+id/dialpad"  
 android:paddingLeft="7dp"  
 android:paddingRight="7dp"  
 android:paddingTop="6dp"  
 android:paddingBottom="6dp"  
 android:layout_gravity="center"  
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content"  
 android:layout_marginBottom="5dp"> 
  
  <ImageButton android:id="@+id/one"  
    android:src="@drawable/dial_num_1_no_vm"  
    style="@style/dial_btn_style"  
    /> 
     
  <ImageButton android:id="@+id/two"  
    android:src="@drawable/dial_num_2"  
    style="@style/dial_btn_style"/>  
     
  <ImageButton android:id="@+id/three"  
    android:src="@drawable/dial_num_3"  
    style="@style/dial_btn_style"/>  
     
  <ImageButton android:id="@+id/four"  
    android:src="@drawable/dial_num_4"  
    style="@style/dial_btn_style"/>  
     
  <ImageButton android:id="@+id/five"  
    android:src="@drawable/dial_num_5"  
    style="@style/dial_btn_style"/> 
     
  <ImageButton android:id="@+id/six"  
    android:src="@drawable/dial_num_6"  
    style="@style/dial_btn_style"/>  
     
  <ImageButton android:id="@+id/seven"  
    android:src="@drawable/dial_num_7"  
    style="@style/dial_btn_style"/> 
     
  <ImageButton android:id="@+id/eight"  
    android:src="@drawable/dial_num_8"  
    style="@style/dial_btn_style"/> 
     
  <ImageButton android:id="@+id/nine"  
    android:src="@drawable/dial_num_9"  
    style="@style/dial_btn_style"/>  
     
  <ImageButton android:id="@+id/star"  
    android:src="@drawable/dial_num_star"  
    style="@style/dial_btn_style"/>   
     
  <ImageButton android:id="@+id/zero"  
    android:src="@drawable/dial_num_0"  
    style="@style/dial_btn_style"/>   
     
  <ImageButton android:id="@+id/pound"  
    android:src="@drawable/dial_num_pound"  
    style="@style/dial_btn_style"/>                                                    
   
</demo.phone.card.MyPhoneCard> 

这样，就实现了上图的小键盘。这个例子参考Android自带电话应用的实现。可见，在开发中，灵活运用自定义的控件，可以实现独特而富有魅力的效果！

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