Android自定義View—滑動開關

MainActivity如下:<喎?/kf/ware/vc/" target="_blank" class="keylink">vcD4KPHByZSBjbGFzcz0="brush:java;">package cc.testview3; import cc.testview3.SwitchView.SwitchChangedListener; import android.os.Bundle; import android.widget.Toast; import android.app.Activity; /** * Demo描述: * 自定義View實現滑動開關 * * 測試設備: * 分辨率為480x854 */ public class MainActivity extends Activity { private SwitchView mSwitchView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); init(); } private void init(){ mSwitchView=(SwitchView) findViewById(R.id.switchView); mSwitchView.initSwitchStatus(true); mSwitchView.setOnSwitchChangedListener(new SwitchChangedListenerImpl()); } private class SwitchChangedListenerImpl implements SwitchChangedListener{ @Override public void OnChanged(boolean currentStatus) { Toast.makeText(MainActivity.this, "currentIsOff?-->"+currentStatus, Toast.LENGTH_SHORT).show(); } } }

SwitchView如下:

package cc.testview3;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class SwitchView extends View  {
	private Bitmap mOnBitmap;
	private Bitmap mOffBitmap;
	private Bitmap mDotBitmap;
	private float currentX;
	private boolean currentIsSlipping=false;
	private boolean currentIsOff;
	private SwitchChangedListener mSwitchChangedListener;
    private int dotWidth;
    private int switchWidth;
	public SwitchView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initSwitchView();
	}

	public SwitchView(Context context, AttributeSet attrs) {
		super(context, attrs);
		initSwitchView();
	}

	public SwitchView(Context context) {
		super(context);
		initSwitchView();
	}
	
	private void initSwitchView(){
		mOnBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.on);
		mOffBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.off);
		mDotBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.dot);
		dotWidth=mDotBitmap.getWidth();
		switchWidth=mOnBitmap.getWidth();
		this.setOnTouchListener(new TouchListenerImpl());
	}
	
	public void initSwitchStatus(boolean isOff){
		if (isOff) {
			currentX=switchWidth;
		} else {
			currentX=0;
		}
		currentIsOff=isOff;
	}
	
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
	}
	
	
	@Override
	protected void onLayout(boolean changed, int left, int top, int right,int bottom) {
		super.onLayout(changed, left, top, right, bottom);
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		Matrix matrix=new Matrix();
		Paint paint=new Paint();
		
		//先畫出開關的背景(關/開)
		if (currentIsOff) {
			canvas.drawBitmap(mOffBitmap, matrix, paint);
		} else {
			canvas.drawBitmap(mOnBitmap, matrix, paint);
		}
		
		//再畫出滑塊
		//1 在滑動中(if),滑塊的left就是不斷變化的currentX
		//2 手指抬起後(else)停止滑動時.此時的開關應該在左右
		//  其中一側處於開或者關的狀態
		if (currentIsSlipping) {
			canvas.drawBitmap(mDotBitmap, currentX, 17, paint);
		} else {
			if (currentIsOff) {
				canvas.drawBitmap(mDotBitmap, currentX-dotWidth, 17, paint); 
			}else{
				canvas.drawBitmap(mDotBitmap, currentX, 17, paint); 
			}
		}
	}
	
	private class TouchListenerImpl implements OnTouchListener{
		@Override
		public boolean onTouch(View v, MotionEvent event) {
			switch (event.getAction()) {
			case MotionEvent.ACTION_DOWN:
				
				break;
			case MotionEvent.ACTION_MOVE:
				currentIsSlipping=true;
				currentX = event.getX();
				if (currentX>switchWidth/2) {
					currentIsOff=true;
				}else {
					currentIsOff=false;
				}
				
				//防止向右邊滑動時越界
				if (event.getX()>switchWidth-dotWidth) {
					currentX = switchWidth-dotWidth;
					currentIsOff=true;
				}
				//防止向左邊滑動時越界
				if (event.getX()<0) {
					currentX=0;
					currentIsOff=false;
				}
				//重繪!!!
				invalidate();
				break;
			case MotionEvent.ACTION_UP:
				currentIsSlipping=false;
				currentX = event.getX();
				//抬起時若(if)已經超過開關一般的長度,則讓其處於關閉的狀態
				//否則(else)讓其處於打開的狀態
				if (currentX >= switchWidth / 2) {
					currentX = switchWidth;
					currentIsOff=true;
				} else {
					currentX = 0;
					currentIsOff=false;
				}
				if (mSwitchChangedListener != null) {
					mSwitchChangedListener.OnChanged(currentIsOff);
				}
				// 重繪!!!
				invalidate();
				break;

			default:
				break;
			}

			return true;
		}
		
	}

	// 接口
	public interface SwitchChangedListener {
		public void OnChanged(boolean currentIsOff);
	}
	
	public void setOnSwitchChangedListener(SwitchChangedListener switchChangedListener) {
		this.mSwitchChangedListener = switchChangedListener;
	}

}

main.xml如下: