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, 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;
}
}
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脚本之家网站的支持！
