Android模拟实现滑动解锁界面

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"
android:layout_width="match_parent" android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:gravity="center_horizontal"
tools:context="com.example.a7_.MainActivity">

<com.example.a7_.MyView
 android:layout_alignParentBottom="true"
 android:id="@+id/mv"
 android:background="@mipmap/lockviewbg"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content" />
</RelativeLayout>

package com.example.a7_;

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

 /**
 * Created by Administrator on 2017.05.28.0028.
 */

 public class MyView extends View {

 private final Bitmap slidBitmap;
 private final Bitmap bgBitmap;
 private int startx;
 private int destance;
 private float endx;
 private final Scroller scroller;


 public MyView(Context context, AttributeSet attrs) {
 super(context, attrs);

 //加载图片资源
 slidBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.switch_button);
 bgBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.lockviewbg);
 //创建scroller对象
 scroller = new Scroller(context);
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 //设置自定义控件的宽和高,,以背景图片为标准
 setMeasuredDimension(bgBitmap.getWidth(),bgBitmap.getHeight());
 }

 @Override
 protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 //绘制图片
 canvas.drawBitmap(slidBitmap,0,0,null);
 }

 //设置滑块的触摸事件
 @Override
 public boolean onTouchEvent(MotionEvent event) {
 switch (event.getAction()){
  case MotionEvent.ACTION_DOWN:
  //当手指按下的时候,记录坐标
  startx = (int) event.getX();
  break;
  case MotionEvent.ACTION_MOVE:
  //当手指移动的时候,记录移动的距离
  destance = (int)(event.getX()-startx);
  //限制滑块移动的区间
  if (destance<0){
   destance = 0;
  }else if (destance>bgBitmap.getWidth()-slidBitmap.getWidth()){
   destance = bgBitmap.getWidth()-slidBitmap.getWidth();
  }
  //将滑块移动至该位置
  scrollTo( -destance,0);
  break;
  case MotionEvent.ACTION_UP:
  //当手指离开时,记录手指离开的位置
  if (destance<bgBitmap.getWidth()-slidBitmap.getWidth()){
   //手指抬起时,如果滑块不在右边,那就让他回到左边
   startx = destance;
   int dx = 0-destance;
   scroller.startScroll(startx,0,dx,0);
   invalidate();
  }else {
   //开启解锁
   listener.onUnlock(this);
  }
  break;
 }
 invalidate();
 return true;
 }

 //重写computeScroll方法 调用invalidate之后 会调用draw draw会调用到这个computeScroll
 @Override
 public void computeScroll() {
 if (scroller.computeScrollOffset()){
  //获取滑块当前的位置
  int currx = scroller.getCurrX();
  scrollTo(-currx,0);
  //重新绘制
  invalidate();
 }
 }

 //设置一个解锁的接口
 interface onUnLockListener{
 void onUnlock(MyView view);
 }

 private onUnLockListener listener;

 public void setOnLockListener(onUnLockListener listener){
  this.listener = listener;
 }

 }

##核心代码

 package com.example.a7_;

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;

 public class MainActivity extends AppCompatActivity {

 private MyView myView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 //初始化控件
 myView = (MyView) findViewById(R.id.mv);
 //设置监听事件
 myView.setOnLockListener(new MyView.onUnLockListener() {
  @Override
  public void onUnlock(MyView view) {
  //触发监听,结束页面
  finish();
  }
 });
 }
 }