我希望我的应用程序能够识别用户在手机屏幕上从右向左滑动。

如何做到这一点?


当前回答

这是一个简单的Android代码,用于检测手势方向

在MainActivity.java和activity_main.xml中编写如下代码:

MainActivity.java

import java.util.ArrayList;

import android.app.Activity;
import android.gesture.Gesture;
import android.gesture.GestureLibraries;
import android.gesture.GestureLibrary;
import android.gesture.GestureOverlayView;
import android.gesture.GestureOverlayView.OnGesturePerformedListener;
import android.gesture.GestureStroke;
import android.gesture.Prediction;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity implements
        OnGesturePerformedListener {

    GestureOverlayView gesture;
    GestureLibrary lib;
    ArrayList<Prediction> prediction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lib = GestureLibraries.fromRawResource(MainActivity.this,
                R.id.gestureOverlayView1);
        gesture = (GestureOverlayView) findViewById(R.id.gestureOverlayView1);
        gesture.addOnGesturePerformedListener(this);
    }

    @Override
    public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
        ArrayList<GestureStroke> strokeList = gesture.getStrokes();
        // prediction = lib.recognize(gesture);
        float f[] = strokeList.get(0).points;
        String str = "";

        if (f[0] < f[f.length - 2]) {
            str = "Right gesture";
        } else if (f[0] > f[f.length - 2]) {
            str = "Left gesture";
        } else {
            str = "no direction";
        }
        Toast.makeText(getApplicationContext(), str, Toast.LENGTH_LONG).show();

    }

}

activity_main.xml

<android.gesture.GestureOverlayView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android1="http://schemas.android.com/apk/res/android"
    xmlns:android2="http://schemas.android.com/apk/res/android"
    android:id="@+id/gestureOverlayView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android1:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw gesture"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</android.gesture.GestureOverlayView>

其他回答

这是一个简单的Android代码,用于检测手势方向

在MainActivity.java和activity_main.xml中编写如下代码:

MainActivity.java

import java.util.ArrayList;

import android.app.Activity;
import android.gesture.Gesture;
import android.gesture.GestureLibraries;
import android.gesture.GestureLibrary;
import android.gesture.GestureOverlayView;
import android.gesture.GestureOverlayView.OnGesturePerformedListener;
import android.gesture.GestureStroke;
import android.gesture.Prediction;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity implements
        OnGesturePerformedListener {

    GestureOverlayView gesture;
    GestureLibrary lib;
    ArrayList<Prediction> prediction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lib = GestureLibraries.fromRawResource(MainActivity.this,
                R.id.gestureOverlayView1);
        gesture = (GestureOverlayView) findViewById(R.id.gestureOverlayView1);
        gesture.addOnGesturePerformedListener(this);
    }

    @Override
    public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
        ArrayList<GestureStroke> strokeList = gesture.getStrokes();
        // prediction = lib.recognize(gesture);
        float f[] = strokeList.get(0).points;
        String str = "";

        if (f[0] < f[f.length - 2]) {
            str = "Right gesture";
        } else if (f[0] > f[f.length - 2]) {
            str = "Left gesture";
        } else {
            str = "no direction";
        }
        Toast.makeText(getApplicationContext(), str, Toast.LENGTH_LONG).show();

    }

}

activity_main.xml

<android.gesture.GestureOverlayView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android1="http://schemas.android.com/apk/res/android"
    xmlns:android2="http://schemas.android.com/apk/res/android"
    android:id="@+id/gestureOverlayView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android1:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw gesture"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</android.gesture.GestureOverlayView>

这段代码检测左右滑动,避免了废弃的API调用,并对之前的答案进行了其他改进。

/**
 * Detects left and right swipes across a view.
 */
public class OnSwipeTouchListener implements OnTouchListener {

    private final GestureDetector gestureDetector;

    public OnSwipeTouchListener(Context context) {
        gestureDetector = new GestureDetector(context, new GestureListener());
    }

    public void onSwipeLeft() {
    }

    public void onSwipeRight() {
    }

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

    private final class GestureListener extends SimpleOnGestureListener {

        private static final int SWIPE_DISTANCE_THRESHOLD = 100;
        private static final int SWIPE_VELOCITY_THRESHOLD = 100;

        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            float distanceX = e2.getX() - e1.getX();
            float distanceY = e2.getY() - e1.getY();
            if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                if (distanceX > 0)
                    onSwipeRight();
                else
                    onSwipeLeft();
                return true;
            }
            return false;
        }
    }
}

像这样使用它:

view.setOnTouchListener(new OnSwipeTouchListener(context) {
    @Override
    public void onSwipeLeft() {
        // Whatever
    }
});

如果你还需要处理点击事件,这里做一些修改:

public class OnSwipeTouchListener implements OnTouchListener {

    private final GestureDetector gestureDetector = new GestureDetector(new GestureListener());

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

    private final class GestureListener extends SimpleOnGestureListener {

        private static final int SWIPE_THRESHOLD = 100;
        private static final int SWIPE_VELOCITY_THRESHOLD = 100;


        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            boolean result = false;
            try {
                float diffY = e2.getY() - e1.getY();
                float diffX = e2.getX() - e1.getX();
                if (Math.abs(diffX) > Math.abs(diffY)) {
                    if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                        if (diffX > 0) {
                            result = onSwipeRight();
                        } else {
                            result = onSwipeLeft();
                        }
                    }
                } else {
                    if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
                        if (diffY > 0) {
                            result = onSwipeBottom();
                        } else {
                            result = onSwipeTop();
                        }
                    }
                }
            } catch (Exception exception) {
                exception.printStackTrace();
            }
            return result;
        }
    }

    public boolean onSwipeRight() {
        return false;
    }

    public boolean onSwipeLeft() {
        return false;
    }

    public boolean onSwipeTop() {
        return false;
    }

    public boolean onSwipeBottom() {
        return false;
    }
}

以及示例用法:

    background.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View arg0) {
            toggleSomething();
        }
    });
    background.setOnTouchListener(new OnSwipeTouchListener() {
        public boolean onSwipeTop() {
            Toast.makeText(MainActivity.this, "top", Toast.LENGTH_SHORT).show();
            return true;
        }
        public boolean onSwipeRight() {
            Toast.makeText(MainActivity.this, "right", Toast.LENGTH_SHORT).show();
            return true;
        }
        public boolean onSwipeLeft() {
            Toast.makeText(MainActivity.this, "left", Toast.LENGTH_SHORT).show();
            return true;
        }
        public boolean onSwipeBottom() {
            Toast.makeText(MainActivity.this, "bottom", Toast.LENGTH_SHORT).show();
            return true;
        }
    });

@Edward Brey的方法很有效。如果有人也想复制和粘贴导入的OnSwipeTouchListener,他们是:

 import android.content.Context;
 import android.view.GestureDetector;
 import android.view.GestureDetector.SimpleOnGestureListener;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnTouchListener;

If you want to display some buttons with actions when an list item is swipe are a lot of libraries on the internet that have this behavior. I implemented the library that I found on the internet and I am very satisfied. It is very simple to use and very quick. I improved the original library and I added a new click listener for item click. Also I added font awesome library (http://fortawesome.github.io/Font-Awesome/) and now you can simply add a new item title and specify the icon name from font awesome.

这是github的链接