Android学习札记2：滑动开关的实现

  

  

之前已经把这个工程共享到eoe论坛上了，原文链接：

http://www.eoeandroid.com/thread-156596-1-1.html

MySlipSwitch:

package com.qing;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.graphics.Rect;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;public class MySlipSwitch extends View implements OnTouchListener {//开关开启时的背景，关闭时的背景，滑动按钮private Bitmap switch_on_Bkg, switch_off_Bkg, slip_Btn;private Rect on_Rect, off_Rect;//是否正在滑动private boolean isSlipping = false;//当前开关状态，true为开启，false为关闭private boolean isSwitchOn = false;//手指按下时的水平坐标X，当前的水平坐标Xprivate float previousX, currentX;//开关监听器private OnSwitchListener onSwitchListener;//是否设置了开关监听器private boolean isSwitchListenerOn = false;public MySlipSwitch(Context context) {super(context);init();}public MySlipSwitch(Context context, AttributeSet attrs) {super(context, attrs);init();}private void init() {setOnTouchListener(this);}protected void setImageResource(int switchOnBkg, int switchOffBkg, int slipBtn) {switch_on_Bkg = BitmapFactory.decodeResource(getResources(), switchOnBkg);switch_off_Bkg = BitmapFactory.decodeResource(getResources(), switchOffBkg);slip_Btn = BitmapFactory.decodeResource(getResources(), slipBtn);//右半边Rect，即滑动按钮在右半边时表示开关开启on_Rect = new Rect(switch_off_Bkg.getWidth() - slip_Btn.getWidth(), 0, switch_off_Bkg.getWidth(), slip_Btn.getHeight());//左半边Rect，即滑动按钮在左半边时表示开关关闭off_Rect = new Rect(0, 0, slip_Btn.getWidth(), slip_Btn.getHeight());}protected void setSwitchState(boolean switchState) {isSwitchOn = switchState;}protected boolean getSwitchState() {return isSwitchOn;}protected void updateSwitchState(boolean switchState) {isSwitchOn = switchState;invalidate();}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);Matrix matrix = new Matrix();Paint paint = new Paint();//滑动按钮的左边坐标float left_SlipBtn;//手指滑动到左半边的时候表示开关为关闭状态，滑动到右半边的时候表示开关为开启状态if(currentX < (switch_on_Bkg.getWidth() / 2)) {canvas.drawBitmap(switch_off_Bkg, matrix, paint);} else {canvas.drawBitmap(switch_on_Bkg, matrix, paint);}//判断当前是否正在滑动if(isSlipping) {if(currentX > switch_on_Bkg.getWidth()) {left_SlipBtn = switch_on_Bkg.getWidth() - slip_Btn.getWidth();} else {left_SlipBtn = currentX - slip_Btn.getWidth() / 2;}} else {//根据当前的开关状态设置滑动按钮的位置if(isSwitchOn) {left_SlipBtn = on_Rect.left;} else {left_SlipBtn = off_Rect.left;}}//对滑动按钮的位置进行异常判断if(left_SlipBtn < 0) {left_SlipBtn = 0;} else if(left_SlipBtn > switch_on_Bkg.getWidth() - slip_Btn.getWidth()) {left_SlipBtn = switch_on_Bkg.getWidth() - slip_Btn.getWidth();}canvas.drawBitmap(slip_Btn, left_SlipBtn, 0, paint);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// TODO Auto-generated method stubsetMeasuredDimension(switch_on_Bkg.getWidth(), switch_on_Bkg.getHeight());}@Overridepublic boolean onTouch(View v, MotionEvent event) {// TODO Auto-generated method stubswitch(event.getAction()) {//滑动case MotionEvent.ACTION_MOVE:currentX = event.getX();break;//按下case MotionEvent.ACTION_DOWN:if(event.getX() > switch_on_Bkg.getWidth() || event.getY() > switch_on_Bkg.getHeight()) {return false;}isSlipping = true;previousX = event.getX();currentX = previousX;break;//松开case MotionEvent.ACTION_UP:isSlipping = false;//松开前开关的状态boolean previousSwitchState  = isSwitchOn;if(event.getX() >= (switch_on_Bkg.getWidth() / 2)) {isSwitchOn = true;} else {isSwitchOn = false;}//如果设置了监听器，则调用此方法if(isSwitchListenerOn && (previousSwitchState != isSwitchOn)) {onSwitchListener.onSwitched(isSwitchOn);}break;default:break;}//重新绘制控件invalidate();return true;}public void setOnSwitchListener(OnSwitchListener listener) {onSwitchListener = listener;isSwitchListenerOn = true;}public interface OnSwitchListener {abstract void onSwitched(boolean isSwitchOn);}}

MainActivity:

package com.qing;import com.qing.MySlipSwitch.OnSwitchListener;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.Toast;public class MainActivity extends Activity {    private Button switch_Btn;private MySlipSwitch slipswitch_MSL;/** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                slipswitch_MSL = (MySlipSwitch)findViewById(R.id.main_myslipswitch);        slipswitch_MSL.setImageResource(R.drawable.bkg_switch, R.drawable.bkg_switch, R.drawable.btn_slip);        slipswitch_MSL.setSwitchState(true);        slipswitch_MSL.setOnSwitchListener(new OnSwitchListener() {@Overridepublic void onSwitched(boolean isSwitchOn) {// TODO Auto-generated method stubif(isSwitchOn) {Toast.makeText(MainActivity.this, "开关已经开启", 300).show();} else {Toast.makeText(MainActivity.this, "开关已经关闭", 300).show();}}});                switch_Btn = (Button)findViewById(R.id.main_button_switch);        switch_Btn.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubslipswitch_MSL.updateSwitchState(!slipswitch_MSL.getSwitchState());if(slipswitch_MSL.getSwitchState()) {Toast.makeText(MainActivity.this, "开关已经开启", 300).show();} else {Toast.makeText(MainActivity.this, "开关已经关闭", 300).show();}}});    }}