截屏和储存

最新推荐文章于 2022-08-05 10:57:29 发布

xinlindezhuangyuan

最新推荐文章于 2022-08-05 10:57:29 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/yanPingWang_8/article/details/81350215

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本文介绍了一个简单的Android应用，该应用包含手势识别功能并能够保存图片到设备相册。通过自定义View和实现GestureDetector接口，可以有效识别多种手势如单击、长按等，并通过自定义方法保存图片。

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<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.mac.a1.MainActivity">

    <LinearLayout
        android:layout_width="368dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical"
        tools:layout_editor_absoluteY="0dp"
        tools:layout_editor_absoluteX="8dp">

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@mipmap/guanweitu" />

        <ImageButton
            android:id="@+id/keepalbum"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="#ffffff"
            android:src="@mipmap/baocunxiangce" />
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

MainActivity:

package com.example.mac.a1;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageButton;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private Bitmap bitmap;
    private GestureDetector mGestureDetector;//添加手势
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ImageButton keepalbumTV = (ImageButton) findViewById(R.id.keepalbum);

        bitmap = BitmapFactory.decodeResource(getResources(),
                R.mipmap.guanweitu);// 获取图片
        keepalbumTV.setOnClickListener(this);
//        添加手势
        mGestureDetector = new GestureDetector(this, new MyGestureListener(this));
}
    @Override
    public void onClick(View view) {

        Preservation_Utils.saveImageToGallery(MainActivity.this,
                bitmap);
    }

//    触摸事件
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return mGestureDetector.onTouchEvent(event);
    }
}

/*
也可以在自定义的View里面设置手势识别：
package noodies.blog.youkuaiyun.com;

import android.content.Context;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;

public class MyView extends View {
    private GestureDetector mGestureDetector;
    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);

        mGestureDetector = new GestureDetector(context, new MyGestureListener(context));

        setLongClickable(true);

        this.setOnTouchListener(new OnTouchListener() {

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

        });
    }
}

陷阱
对于自定义View，使用手势识别有两处陷阱可能会浪费你的不少时间。
1：View必须设置longClickable为true，否则手势识别无法正确工作，只会返回Down, Show, Long三种手势
2：必须在View的onTouchListener中调用手势识别，而不能像Activity一样重载onTouchEvent，否则同样手势识别无法正确工作

测试结果
下面是各种操作返回的手势序列，数值0表示触摸屏按下，1表示抬起
单击：down 0, single up 1, single conf 0
短按：down 0, show 0, single up 1
长按：down 0, show 0, long 0
双击：down 0, single up 1, double 0, double event 0, down 0, double event 1
滚动：down 0, (show 0), scrool 2...
滑动：down 0, (show 0), scrool 2..., fling 1

 */

MyGestureListener:
package com.example.mac.a1;
import android.content.Context;
import android.view.MotionEvent;
import android.view.GestureDetector;
import android.widget.Toast;
/**
 * Created by mac on 2017/12/17.
 */

public class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
    private Context mContext;
    MyGestureListener(Context context) {
        mContext = context;
    }
    @Override
    public boolean onDown(MotionEvent e) {
        Toast.makeText(mContext, "DOWN " + e.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {
        Toast.makeText(mContext, "SHOW " + e.getAction(), Toast.LENGTH_SHORT).show();
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        Toast.makeText(mContext, "SINGLE UP " + e.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2,
                            float distanceX, float distanceY) {
        Toast.makeText(mContext, "SCROLL " + e2.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        Toast.makeText(mContext, "LONG " + e.getAction(), Toast.LENGTH_SHORT).show();
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                           float velocityY) {
        Toast.makeText(mContext, "FLING " + e2.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        Toast.makeText(mContext, "DOUBLE " + e.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent e) {
        Toast.makeText(mContext, "DOUBLE EVENT " + e.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        Toast.makeText(mContext, "SINGLE CONF " + e.getAction(), Toast.LENGTH_SHORT).show();
        return false;
    }
}

Preservation_Utils:

package com.example.mac.a1;

import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.net.Uri;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;

public class Preservation_Utils {
      public static void saveImageToGallery(Context context,Bitmap bitmap) {
         File appDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), "huakong1");
         if (!appDir.exists()) {
               appDir.mkdirs();
             }
         String fileName = System.currentTimeMillis() + ".jpg";
          File file = new File(appDir, fileName);
          try {
            FileOutputStream fos = new FileOutputStream(file);
            bitmap.compress(CompressFormat.JPEG, 100, fos);
            fos.close();
                //保存图片后发送广播通知更新数据库
                Uri uri = Uri.fromFile(file);
                context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, uri));
          } catch (Exception e) {
            e.printStackTrace();
          } finally {
            //if (type == ScannerType.RECEIVER) {//onReceiver
//            ScannerByReceiver(context, file.getAbsolutePath());
            //}// else if (type == ScannerType.MEDIA) {
//            ScannerByMedia(context, file.getAbsolutePath());
//          }
            if (!bitmap.isRecycled()) {
              // bitmap.recycle();
            }
            Toast.makeText(context, "保存成功" , Toast.LENGTH_SHORT).show();
          }
      }
       /** Receiver**/

        private static void ScannerByReceiver(Context context, String path) {
          context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://"
              + path)));
          Log.v("TAG", "receiver scanner completed");
        }
   }

ScannerUtilsid:

package com.example.mac.a1;

import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.net.Uri;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
/**
 * @author: HouSheng
 *
 * @类 说 明: 图片扫描工具类
 */
public class ScannerUtilsid {
    // 扫描的三种方式
    public static enum ScannerType {//枚举
        RECEIVER, MEDIA
    }

    // 首先保存图片
    public static void saveImageToGallery(Context context, Bitmap bitmap, ScannerType type) {
        File appDir = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), "华控通");
        if (!appDir.exists()) {
// 目录不存在 则创建
            appDir.mkdirs();
        }
        String fileName = "华控通" + ".png";
        File file = new File(appDir, fileName);
        try {
            FileOutputStream fos = new FileOutputStream(file);
            bitmap.compress(CompressFormat.PNG, 100, fos); // 保存bitmap至本地
            fos.flush();
            fos.close();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (type == ScannerType.RECEIVER) {//onReceiver
                ScannerByReceiver(context, file.getAbsolutePath());
            }// else if (type == ScannerType.MEDIA) {

            if (!bitmap.isRecycled()) {
// bitmap.recycle(); 当存储大图片时，为避免出现OOM ，及时回收Bitmap
                System.gc(); // 通知系统回收
            }
            Toast.makeText(context, "图片保存为" + file.getAbsolutePath(), Toast.LENGTH_SHORT).show();
        }
    }

    /** Receiver扫描更新图库图片 **/
    static void ScannerByReceiver(Context context, String path) {
        context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://"
                + path)));
        Log.v("TAG", "receiver scanner completed");
    }
}