Android中的Fling Gesture和Webview

Question

我有一个webview控件,需要支持Android中的fling手势才能显示新记录(加载新数据).这是在扩展Activity的类中发生的.我见过的所有示例都展示了如何为textview实现手势支持,但对于webview却没有.

我需要对左右翼进行不同的动作.任何代码帮助将不胜感激,因为这完全让我难过.

这是我基本的onCreate和我的课程

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.SQLException;
import android.os.Bundle;
import android.text.Html;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;

import android.webkit.WebView;

public class ArticleActivity extends Activity   {

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);



    Window  w = getWindow();

     w.requestFeature(Window.FEATURE_LEFT_ICON);

     WebView webview = new WebView(this);
     setContentView(webview); 



     w.setFeatureDrawableResource(Window.FEATURE_LEFT_ICON,
     R.drawable.gq);




    setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL);
    populateFields();
    webview.loadData(question + answer, "text/html", "utf-8");



  //   
}
private void populateFields() {

....


}

}

Answer 1

创建一个GestureListener和一个GestureDetector.通过覆盖webview的onTouchEvent来调用GestureDetector.onTouchEvent.

您也可以直接覆盖Activity onTouchEvent btw.如果需要,我可以发布一些代码.

编辑:代码按要求.

public class Main extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        MyWebView webview = new MyWebView(this);
        setContentView(webview);
    }

    class MyWebView extends WebView {
        Context context;
        GestureDetector gd;

        public MyWebView(Context context) {
            super(context);

            this.context = context;
            gd = new GestureDetector(context, sogl);
        }

        @Override
        public boolean onTouchEvent(MotionEvent event) {
            return gd.onTouchEvent(event);
        }

        GestureDetector.SimpleOnGestureListener sogl = new GestureDetector.SimpleOnGestureListener() {
            public boolean onDown(MotionEvent event) {
                return true;
            }

            public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
                if (event1.getRawX() > event2.getRawX()) {
                    show_toast("swipe left");
                } else {
                    show_toast("swipe right");
                }
                return true;
            }
        };

        void show_toast(final String text) {
            Toast t = Toast.makeText(context, text, Toast.LENGTH_SHORT);
            t.show();
        }
    }
}

@littleFluffyKitty.我默认设置WebView触摸事件,当你调出缩放控件等时？我没有测试过.我发现实现自己的手势检测效果最好(不确定它是否最适合WebView).您需要将触摸事件视为三个不同的组件.按下,移动(如果有的话)和按下按钮,按下,移动,释放总是发生.

如果你在onDown上返回false,那么动作应该传递给WebView触摸事件处理程序但是iirc它会停止传递给GestureDetector的后续事件.这是我实现自己的基于Android源的一半原因.iirc我从索尼爱立信教程中得到了这个想法,可以从市场上下载.这是显示代码的3D列表,非常容易适应.

Answer 2

我更新了代码,如果用户没有使用,现在可以调用本机事件处理程序

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.webkit.WebView;

public class MyWebView extends WebView {
    private boolean flinged;

    private static final int SWIPE_MIN_DISTANCE = 320;
    private static final int SWIPE_MAX_OFF_PATH = 250;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;

    public MyWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        gd = new GestureDetector(context, sogl);
    }

    GestureDetector gd;


    @Override
    public boolean onTouchEvent(MotionEvent event) {
         gd.onTouchEvent(event);
         if (flinged) {
             flinged = false;
             return true;
         } else {
             return super.onTouchEvent(event);
         }
    }

    GestureDetector.SimpleOnGestureListener sogl = new GestureDetector.SimpleOnGestureListener() {
    // your fling code here
        public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
            if (event1.getX() < 1200 && event1.getX() > 80) {
                return false;
            }
            if (Math.abs(event1.getY() - event1.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            if(event1.getX() - event2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                loadUrl("javascript:changePage('LEFT')");
                Log.i("Swiped","swipe left");
                flinged = true;
            } else if (event2.getX() - event1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                loadUrl("javascript:changePage('RIGHT')");
                Log.i("Swiped","swipe right");
                flinged = true;
            }
            return true;
        }
    };
}