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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