Android中View(视图)绘制不同状态背景图片

package com.qin.selectionDrawable; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.drawable.Drawable; import android.os.Bundle; import android.util.AttributeSet; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.LinearLayout; import android.widget.TextView; import android.graphics.drawable.StateListDrawable; /** * * @author http://http://blog.csdn.net/qinjuning */ //自定义View public class CustomView extends View /*extends Button*/ { private static String TAG = "TackTextView"; private Context mContext = null; private Drawable mBackground = null; private boolean mBGSizeChanged = true;; //视图View布局(layout)大小是否发生变化 public CustomView(Context context) { super(context); // TODO Auto-generated constructor stub mContext = context; initStateListDrawable(); // 初始化图片资源 } public CustomView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub mContext = context; initStateListDrawable(); // 初始化图片资源 } public CustomView(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub mContext = context; initStateListDrawable(); // 初始化图片资源 } // 初始化图片资源 private void initStateListDrawable() { //有两种方式获取我们的StateListDrawable对象： // 获取方式一、手动构建一个StateListDrawable对象 StateListDrawable statelistDrawable = new StateListDrawable(); int pressed = android.R.attr.state_pressed; int windowfocused = android.R.attr.state_window_focused; int enabled = android.R.attr.state_enabled; int stateFoucesd = android.R.attr.state_focused; //匹配状态时，是一种优先包含的关系。 // "-"号表示该状态值为false .即不匹配 statelistDrawable.addState(new int[] { pressed, windowfocused }, mContext.getResources().getDrawable(R.drawable.btn_power_on_pressed)); statelistDrawable.addState(new int[]{ -pressed, windowfocused }, mContext.getResources().getDrawable(R.drawable.btn_power_on_nor)); //更多其他状态属性 //stateD.addState(new int[]{pressed , windowfocused },mContext.getResources().getDrawable(R.drawable.btn_dialog_selected) ) //stateD.addState(View.EMPTY_STATE_SET, mContext.getResources().getDrawable(R.drawable.btn_dialog_normal)); //statelistDrawable.addState(new int[] { stateFoucesd, windowfocused }, null); mBackground = statelistDrawable; //必须设置回调，当改变状态时，会回掉该View进行invalidate()刷新操作. mBackground.setCallback(this); //取消默认的背景图片，因为我们设置了自己的背景图片了，否则可能造成背景图片重叠。 this.setBackgroundDrawable(null); // 获取方式二、、使用XML获取StateListDrawable对象 // mBackground = mContext.getResources().getDrawable(R.drawable.view_background); } // //在View类中setFrame是隐藏方法 @hide , 而在TexitView/Button类时可以继承该方法 // protected boolean setFrame(int l , int t , int r ,int b){ // // if(getLeft() != l || getTop() != t || getRight()!= r || getBottom() != b){ // mBGSizeChanged = true // } // // return super.setFrame(l , t , l , b); // } protected void drawableStateChanged() { Log.i(TAG, "drawableStateChanged"); Drawable d = mBackground; if (d != null && d.isStateful()) { d.setState(getDrawableState()); //Log.i(TAG, "drawableStateChanged and is 111"); } // //打印各种状态值 // int[] states = d.getState(); // // for (int i = 0; i < states.length; i++) // { // System.out.println("states[" + i + "]" + states[i]); // } // Log.i(TAG, "drawableStateChanged and is 222"); super.drawableStateChanged(); } //验证图片是否相等 , 在invalidateDrawable()会调用此方法，我们需要重写该方法。 protected boolean verifyDrawable(Drawable who) { return who == mBackground || super.verifyDrawable(who); } //draw()过程，绘制背景图片... public void draw(Canvas canvas) { Log.i(TAG, " draw -----"); if (mBackground != null) { if(mBGSizeChanged) { //设置边界范围 mBackground.setBounds(0, 0, getRight() - getLeft(), getBottom() - getTop()); mBGSizeChanged = false ; } if ((getScrollX() | getScrollY()) == 0) //是否偏移 { mBackground.draw(canvas); //绘制当前状态对应的图片 } else { canvas.translate(getScrollX(), getScrollY()); mBackground.draw(canvas); //绘制当前状态对应的图片 canvas.translate(-getScrollX(), -getScrollY()); } } super.draw(canvas); } public void onDraw(Canvas canvas) { canvas.save(); Paint paint = new Paint(); paint.setTextSize(16); paint.setColor(Color.YELLOW); canvas.drawText("自定义View", 0, 20, paint); canvas.drawText("触摸我可以改变图片背景", 0, 40, paint); canvas.restore(); } }