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先給大家展示下效果圖，如果大家感覺不錯，請參考實現代碼
效果圖如下所示：
代碼如下所示：
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;
// 重寫
@Override
public boolean onTouchEvent(MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
// 多指觸控
switch (event.getAction() & event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
Log.e("TAG", "多指移動");
mode = SCALE;
// 兩個手指開始的長度是多少呢？
length = calc(event);
break;
case MotionEvent.ACTION_UP:
length = 1;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
// 1. 單個手指
FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
width, height);
params.setMargins(x, y, 0, 0);
view.setLayoutParams(params);
} else {
// 2. 兩個手指
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;
}
// 類 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類
<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中定義的一個圓的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>
用自定義View的方式實現單點觸控時拖動圖片，跟著拖動點走
QiuView 類
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);
}
// 觸摸事件
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_MOVE) {
point.set(event.getX(), event.getY());
invalidate();
}
return true;
}
}
總結
以上所述是小編給大家介紹的Android自定義一個圖形單點移動縮小的效果，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對億速云網站的支持！
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