一、ZXing

ZXing ("zebra crossing") is an open-source, multi-format 1D/2D barcode image processing library implemented in Java, with ports to other languages.
https://github.com/zxing/zxing

android-zxingLibrary 几行代码快速集成二维码扫描功能
https://github.com/yipianfengye/android-zxingLibrary
可打开默认二维码扫描页面
支持对图片Bitmap的扫描功能
支持对UI的定制化操作
支持对条形码的扫描功能
支持生成二维码操作
支持控制闪光灯开关

1、拍摄识别二维码

1.依赖

compile 'cn.yipianfengye.android:zxing-library:2.2'

2.权限

    <uses-permission android:name="android.permission.CAMERA"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.INTERNET" />

3.初始化

public class App extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        ZXingLibrary.initDisplayOpinion(this);
    }
}

4.mainfest中配置app

    <application
        android:name=".App"

5.拍摄二维码进行识别

Intent intent = new Intent(MainActivity.this, CaptureActivity.class);
startActivityForResult(intent, REQUEST_CODE);

6.扫描结果

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQ_CODE) {
            if (resultCode == RESULT_OK) {
                if (data != null) {
                    Bundle bundle = data.getExtras();
                    if (bundle != null) {
                        int type = bundle.getInt(CodeUtils.RESULT_TYPE);
                        if (type == CodeUtils.RESULT_SUCCESS) {
                            String str = bundle.getString(CodeUtils.RESULT_STRING);
                            Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
                        }
                    }
                }
            }
        }
    }

2、解析手机本地二维码

1.依赖

如上

2.权限

如上

3.初始化

如上

4.mainfest中配置app.

如上

5.manifest中app新加

android:requestLegacyExternalStorage="true"

6.选取图片

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("image/*");
startActivityForResult(intent, REQUEST_IMAGE);

7.扫描结果

            if (requestCode == REQUEST_IMAGE) {
            if (resultCode == RESULT_OK) {
                if (data != null) {
                    Uri uri = data.getData();
                    String path = FileUtil.getFilePathByUri(getApplicationContext(), uri);
                    CodeUtils.analyzeBitmap(path, new CodeUtils.AnalyzeCallback() {
                        @Override
                        public void onAnalyzeSuccess(Bitmap mBitmap, String result) {
                            Toast.makeText(MainActivity.this, "解析结果:" + result, Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onAnalyzeFailed() {
                            Toast.makeText(MainActivity.this, "解析二维码失败", Toast.LENGTH_LONG).show();
                        }
                    });
                }
            }
        }

FileUtil.java

public class FileUtil {
    public static String getFilePathByUri(Context context, Uri uri) {
        if ("content".equalsIgnoreCase(uri.getScheme())) {
            int sdkVersion = Build.VERSION.SDK_INT;
            if (sdkVersion >= 19) {
                return getRealPathFromUriAboveApi19(context, uri);
            }
        }
        return null;
    }

    @SuppressLint("NewApi")
    private static String getRealPathFromUriAboveApi19(Context context, Uri uri) {
        String filePath = null;
        if (DocumentsContract.isDocumentUri(context, uri)) {
            // 如果是document类型的 uri, 则通过document id来进行处理
            String documentId = DocumentsContract.getDocumentId(uri);
            if (isMediaDocument(uri)) { // MediaProvider
                // 使用':'分割
                String type = documentId.split(":")[0];
                String id = documentId.split(":")[1];

                String selection = MediaStore.Images.Media._ID + "=?";
                String[] selectionArgs = {id};

                Uri contentUri = null;
                if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
                } else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
                } else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                }

                filePath = getDataColumn(context, contentUri, selection, selectionArgs);
            }
        }
        return filePath;
    }

    private static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
        String path = null;

        String[] projection = new String[]{MediaStore.Images.Media.DATA};
        Cursor cursor = null;
        try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
            if (cursor != null && cursor.moveToFirst()) {
                int columnIndex = cursor.getColumnIndexOrThrow(projection[0]);
                path = cursor.getString(columnIndex);
            }
        } catch (Exception e) {
            if (cursor != null) {
                cursor.close();
            }
        }
        return path;
    }

    private static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }
}

3、生成二维码

1.准备工作

如上

2.

    private void generateErWeiMa() {
        String str = "wangxianbing";
        ImageView imageView = findViewById(R.id.image_view);
//        Bitmap mBitmap = CodeUtils.createImage(str, 400, 400, null);
        Bitmap mBitmap = CodeUtils.createImage(str, 400, 400, BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher));
        imageView.setImageBitmap(mBitmap);
    }

二、LeakCanary

LeakCanary is a memory leak detection library for Android.
https://github.com/square/leakcanary

LeakCanary automatically detects leaks of the following objects:
-destroyed Activity instances
-destroyed Fragment instances
-destroyed fragment View instances
-cleared ViewModel instances

1.依赖

debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.5'

2.在第一个activity中添加点击事件，点击按钮后打开第二个activity

3.新建一个管理类，模拟管擦着模式

public class Manager {
private static Manager sManager = new Manager();
private Manager(){}
public static Manager getInstance() {
return sManager;
}
List<Callback> mList = new ArrayList<>();
public void register(Callback callback) {
mList.add(callback);
}
public void unregister(Callback callback) {
mList.remove(callback);
}
public static interface Callback {}
}

4.在第二个Activity的onCreate中调用Manager.getInstance().register(this);

5.连续几次打开第二个Activity，查看LeakCanary

图片.png