Android自定义一个图形单点移动缩小的效果

概述先给大家展示下效果图，如果大家感觉不错，请参考实现代码效果图如下所示：

先给大家展示下效果图，如果大家感觉不错，请参考实现代码

效果图如下所示：

代码如下所示：

public class MainActivity extends Activity {  VIEw vIEw;  public static final int DRAG = 1;  public static final int SCALE = 2;  int mode = 1;  int height = 10,wIDth = 10;  @OverrIDe  protected voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    getwindow().requestFeature(Window.FEATURE_NO_Title);    setContentVIEw(R.layout.activity_main);    vIEw = findVIEwByID(R.ID.vIEw);  }  float length = 1;  // 重写  @OverrIDe  public boolean ontouchEvent(MotionEvent event) {    int x = (int) event.getX();    int y = (int) event.getY();    // 多指触控    switch (event.getAction() & event.getActionMasked()) {    case MotionEvent.ACTION_DOWN:      mode = DRAG;      break;    case MotionEvent.ACTION_POINTER_DOWN:      Log.e("TAG","多指移动");      mode = SCALE;      // 两个手指开始的长度是多少呢？      length = calc(event);      break;    case MotionEvent.ACTION_UP:      length = 1;      break;    case MotionEvent.ACTION_MOVE:      if (mode == DRAG) {        // 1. 单个手指        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(            wIDth,height);        params.setmargins(x,y,0);        vIEw.setLayoutParams(params);      } else {        // 2. 两个手指        float beilv = calc(event) / length;        wIDth = (int) (vIEw.getWIDth() * beilv);        height = (int) (vIEw.getHeight() * beilv);        Log.e("TAG",beilv + " " + wIDth + " " + height);        FrameLayout.LayoutParams params = (LayoutParams) vIEw            .getLayoutParams();        params.wIDth = wIDth;        params.height = height;        vIEw.setLayoutParams(params);      }      break;    }    return true;  }  // 类 Ponint  public float calc(MotionEvent event) {    float x1 = event.getX();    float y1 = event.getY();    float x2 = event.getX(1);    float y2 = event.getY(1);    return (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));  }}

xml类

<FrameLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"  xmlns:tools="http://schemas.androID.com/tools"  androID:layout_wIDth="match_parent"  androID:layout_height="match_parent"  tools:context="com.example.lesson6_work1.MainActivity" >  <VIEw    androID:ID="@+ID/vIEw"    androID:layout_wIDth="30dp"    androID:layout_height="30dp"    androID:background="@drawable/oval" /></FrameLayout>

自己在shape中定义的一个圆的oval.xml

<?xml version="1.0" enCoding="utf-8"?><shape xmlns:androID="http://schemas.androID.com/apk/res/androID" androID:shape="oval">  <solID androID:color="@androID:color/holo_red_dark"/></shape>

用自定义view的方式实现单点触控时拖动图片，跟着拖动点走

QiuVIEw 类

public class QiuVIEw extends VIEw {  Paint paint = new Paint();  PointF point = new PointF();  public QiuVIEw(Context context) {    super(context);    paint.setcolor(color.RED);    paint.setAntiAlias(true);    paint.setDither(true);  }  @OverrIDe  protected voID onDraw(Canvas canvas) {    super.onDraw(canvas);    canvas.drawCircle(point.x,point.y,50,paint);  }  //  触摸事件  @OverrIDe  public boolean ontouchEvent(MotionEvent event) {    if (event.getAction() == MotionEvent.ACTION_MOVE) {      point.set(event.getX(),event.getY());      invalIDate();    }    return true;  }}

总结

以上所述是小编给大家介绍的AndroID自定义一个图形单点移动缩小的效果，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对编程小技巧网站的支持！

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