将 Fling 手势添加到图像视图 - Android

Question

好吧，我一直在引用这里的代码： 在网格布局上进行 Fling 手势检测

但就是无法获取让它工作。在我的主要活动中，我定义了一个简单的图像。我想检测图像上的抖动。下面是我的代码。底部的onclick方法是空的。是因为这个吗？我将其留空，因为在其他代码示例中它不是我想要的。我只想弹出一个简单的吐司，说“向右滑动”或“向左滑动”。

public class GestureRightLeft extends Activity implements OnClickListener  {

    ImageView peek;

    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_MAX_OFF_PATH = 250;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;
    private GestureDetector gestureDetector;
    View.OnTouchListener gestureListener;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        peek =(ImageView) findViewById(R.id.peek);
        peek.setImageResource(R.drawable.bluestrip);

        gestureDetector = new GestureDetector(new MyGestureDetector());
        gestureListener = new View.OnTouchListener() {
            public boolean onTouch(View v, MotionEvent event) {
                if (gestureDetector.onTouchEvent(event)) {
                    return true;
                }
                return false;
            }
        };
    }

    class MyGestureDetector extends SimpleOnGestureListener {
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            try {
                if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                    return false;
                // right to left swipe
                if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    Toast.makeText(GestureRightLeft.this, "Left Swipe", Toast.LENGTH_SHORT).show();
                }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    Toast.makeText(GestureRightLeft.this, "Right Swipe", Toast.LENGTH_SHORT).show();
                }
            } catch (Exception e) {
                // nothing
            }
            return false;
        }
    }

    @Override
    public void onClick(View v) {}
}

Answer 1

这是我能想到的最简单的 fllinger 工作版本。
实际上，您可以将其绑定到任何组件，而不仅仅是 ImageView。

public class MyActivity extends Activity {
    private void onCreate() {
        final GestureDetector gdt = new GestureDetector(new GestureListener());
        final ImageView imageView  = (ImageView) findViewById(R.id.image_view);
        imageView.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(final View view, final MotionEvent event) {
                gdt.onTouchEvent(event);
                return true;
            }
        });
    }               

    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;

    private class GestureListener extends SimpleOnGestureListener {
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                return false; // Right to left
            }  else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                return false; // Left to right
            }

            if(e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) {
                return false; // Bottom to top
            }  else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) {
                return false; // Top to bottom
            }
            return false;
        }
    }
}

但 onClickListener 没有活动（如果您不需要捕获任何 onclick 操作）
它不仅捕获水平方向，还捕获垂直方向（如果不需要，只需删除垂直部分），并且水平滑动具有优先级，如您所见。
在方法返回的地方（以及我的评论所在的地方）只需调用您的方法或其他:)

Answer 2

试试这个

imageView.setOnTouchListener(new View.OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (gestureDetector.onTouchEvent(event)) {
                return false;
            }
            return true;
        }
  });

Answer 3

imageView.setOnTouchListener(new View.OnTouchListener() {

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        return !gestureDetector.onTouchEvent(event);
    }
});

Answer 4

一些先决条件

1) setonClick 方法

image.setOnClickListener(this);

2) 在 onTouch() 中设置手势检测

image.setOnTouchListener(new OnTouchListener() {
    GestureDetector gestureDetector = new GestureDetector(new SwingGestureDetection((mContext),image,a));
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        return gestureDetector.onTouchEvent(event);
    }
});

3) 创建 SwingGestureDetection 类并实现所有方法

@Override
public boolean onFling(MotionEvent start, MotionEvent finish, float arg2,float arg3) {
    if (start.getRawX() < finish.getRawX()) {
        System.out.println("next...swing");
    } else {
        System.out.println("previois...swing");
    }
}

4) 在构造函数中传递你的 imageview

public SwingGestureDetection(Context con,ImageView image,int pos) {
    mContext = con;
    this.image = image;
    this.position = pos;
}

这对我来说是完美的工作。如果有任何查询，请发表评论。

Answer 5

尝试阅读：
http://illusionsandroid.blogspot.com/2011 /05/adding-fling-gesture-listener-to-view.html

它允许您将活动实现与自定义侦听器分开。这只是 Alex Orlov 报告的解决方案的重构

Answer 6

如果您不喜欢创建单独的类或使代码变得复杂，
您可以在 OnTouchListener 中创建一个 GestureDetector 变量，并使您的代码更容易

namVyuVar 可以是您需要在其上设置监听器的视图的任何名称

namVyuVar.setOnTouchListener(new View.OnTouchListener()
{
    @Override
    public boolean onTouch(View view, MotionEvent MsnEvtPsgVal)
    {
        flingActionVar.onTouchEvent(MsnEvtPsgVal);
        return true;
    }

    GestureDetector flingActionVar = new GestureDetector(getApplicationContext(), new GestureDetector.SimpleOnGestureListener()
    {
        private static final int flingActionMinDstVac = 120;
        private static final int flingActionMinSpdVac = 200;

        @Override
        public boolean onFling(MotionEvent fstMsnEvtPsgVal, MotionEvent lstMsnEvtPsgVal, float flingActionXcoSpdPsgVal, float flingActionYcoSpdPsgVal)
        {
            if(fstMsnEvtPsgVal.getX() - lstMsnEvtPsgVal.getX() > flingActionMinDstVac && Math.abs(flingActionXcoSpdPsgVal) > flingActionMinSpdVac)
            {
                // TskTdo :=> On Right to Left fling

                return false;
            }
            else if (lstMsnEvtPsgVal.getX() - fstMsnEvtPsgVal.getX() > flingActionMinDstVac && Math.abs(flingActionXcoSpdPsgVal) > flingActionMinSpdVac)
            {
                // TskTdo :=> On Left to Right fling

                return false;
            }

            if(fstMsnEvtPsgVal.getY() - lstMsnEvtPsgVal.getY() > flingActionMinDstVac && Math.abs(flingActionYcoSpdPsgVal) > flingActionMinSpdVac)
            {
                // TskTdo :=> On Bottom to Top fling

                return false;
            }
            else if (lstMsnEvtPsgVal.getY() - fstMsnEvtPsgVal.getY() > flingActionMinDstVac && Math.abs(flingActionYcoSpdPsgVal) > flingActionMinSpdVac)
            {
                // TskTdo :=> On Top to Bottom fling

                return false;
            }
            return false;
        }
    });
});

Answer 7

如果您正在寻找像 ImageView.setOnGestureListener 这样的方法，那么没有。你可以去看一下Android源码。最好的选择是在 View 对象的 onTouch() 中处理它。

这是我能做的最简单的手势检测器。

我有一个名为 GenesMotionDetector.java 的类。下面是它的代码：

package gene.com.motioneventssample;

import android.app.Activity;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class GenesMotionDetector extends Activity implements GestureDetector.OnGestureListener {
    private GestureDetector gestureScanner;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.nothing);
        gestureScanner= new GestureDetector(getBaseContext(),this);
    }

    @Override
    public boolean onTouchEvent(MotionEvent me) {
        System.out.println("Inside onTouchEvent() of GenesMotionDetector.java");
        return gestureScanner.onTouchEvent(me);
    }

    @Override
    public boolean onDown(MotionEvent e) {
        System.out.println("Inside onDown() of GenesMotionDetector.java");
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        System.out.println("Inside onFling() of GenesMotionDetector.java");
        return true;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        System.out.println("Inside onLongPress() of GenesMotionDetector.java");
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        System.out.println("Inside onScroll() of GenesMotionDetector.java");
        return true;
    }

    @Override
    public void onShowPress(MotionEvent e) {
        System.out.println("Inside onShowPress() of GenesMotionDetector.java");
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        System.out.println("Inside onSingleTapUp() of GenesMotionDetector.java");
        return true;
    }
}

该类相应的 XML 布局文件是 Nothing.xml。这是它的代码：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/screen"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/text"
        android:background="#17528c"
        android:text="testing"
        android:layout_width="100dp"
        android:layout_height="200dp" />

    <ImageView
        android:id="@+id/image"
        android:background="#f8af20"
        android:layout_width="100dp"
        android:layout_height="200dp" />
</LinearLayout>

现在，采用我可以制作的最简单的 GestureDetector（从上面）并根据您想要的进行修改，我得到：

package gene.com.motioneventssample;

import android.app.Activity;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.widget.ImageView;

public class GenesMotionDetector3 extends Activity implements GestureDetector.OnGestureListener {
    private GestureDetector gestureScanner;
    ImageView mView3;

    View.OnTouchListener gestureListener;
    MotionEvent initialME, finalME;
    private VelocityTracker mVelocityTracker = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.nothing);


        mView3 = (ImageView) findViewById(R.id.image);

        // Gesture detection
        gestureScanner = new GestureDetector(getBaseContext(), this);

        gestureListener = new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch(event.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        initialME= event;

                        if(mVelocityTracker == null) {
                            // Retrieve a new VelocityTracker object to watch the velocity of a motion.
                            mVelocityTracker = VelocityTracker.obtain();
                        }
                        else {
                            // Reset the velocity tracker back to its initial state.
                            mVelocityTracker.clear();
                        }
                        // Add a user's movement to the tracker.
                        mVelocityTracker.addMovement(event);

                        break;
                    case MotionEvent.ACTION_MOVE:
                        mVelocityTracker.addMovement(event);
                        // When you want to determine the velocity, call
                        // computeCurrentVelocity(). Then call getXVelocity()
                        // and getYVelocity() to retrieve the velocity for each pointer ID.
                        mVelocityTracker.computeCurrentVelocity(1000);
                        break;
                    case MotionEvent.ACTION_UP:
                        finalME=event;
                        break;
                    case MotionEvent.ACTION_CANCEL:
                        // Return a VelocityTracker object back to be re-used by others.
                        mVelocityTracker.recycle();
                        break;
                }
                return onFling(initialME, finalME, mVelocityTracker.getXVelocity(), mVelocityTracker.getYVelocity());
                //return false;
            }
        };

        mView3.setOnTouchListener(gestureListener);
    }

    @Override
    public boolean onTouchEvent(MotionEvent me) {
        System.out.println("Inside onTouchEvent() of GenesMotionDetector.java");

        return gestureScanner.onTouchEvent(me);
    }

    @Override
    public boolean onDown(MotionEvent e) {
        System.out.println("Inside onDown() of GenesMotionDetector.java");
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        System.out.println("Inside onFling() of GenesMotionDetector.java");
        System.out.println("e1= "+ e1);
        System.out.println("e2= "+ e2);
        System.out.println("velocityX= "+ velocityX);
        System.out.println("velocityY= "+ velocityY);
        return true;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        System.out.println("Inside onLongPress() of GenesMotionDetector.java");
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        System.out.println("Inside onScroll() of GenesMotionDetector.java");
        return true;
    }

    @Override
    public void onShowPress(MotionEvent e) {
        System.out.println("Inside onShowPress() of GenesMotionDetector.java");
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        System.out.println("Inside onSingleTapUp() of GenesMotionDetector.java");
        return true;
    }
}

您不妨在 onTouch() 中处理所有内容。我基本上是在 onTouch 中获取手势并将其传递给 onFling()。

Answer 8

使用 ImageView 设计布局。
添加setOnTouchListener到imageView。imageview.setOnTouchListener(this)。添加未实现的方法View.OnTouchListener。然后添加onTouch方法你可以实现你的手势逻辑。这个示例告诉你从左到右和从右到左的手势，

float x1,x2;
float y1, y2;

@Override
public boolean onTouch(View view, MotionEvent event) {
    switch ( event.getAction() ){

        case MotionEvent.ACTION_DOWN:{
            x1 = event.getX();
            y1 = event.getY();
            break;
        }

        case MotionEvent.ACTION_UP:{
            x2 = event.getX();
            y2 = event.getY();

            if ( x1<x2 ) {
                //implement what you need to do here
            }
            if ( x1>x2 ) {
                //implement what you need to do here
            }
            break;
        }
    }
    return false;
}

Answer 9

kotlin 的快速示例：

val flingGesture = GestureDetector(requireContext(), object : GestureDetector.SimpleOnGestureListener() {
    override fun onFling(e1: MotionEvent?, e2: MotionEvent?, velocityX: Float, velocityY: Float): Boolean {
        // your action here
        return true
    }
})

设置为任何视图：

imageView.setOnTouchListener{ _, motionEvent ->
    flingGesture.onTouchEvent(motionEvent)
    return@setOnTouchListener true
}