Android中調用系統管理器選擇文件並返回絕對路徑

選擇文件的時候，若是使用的是第三方軟件，通常是直接返回絕對路徑的Uri，若是是系統的，則會返回媒體庫的xxxx，因此單純一種方式選擇文件，極可能拿到的絕對路徑是錯的或者是空的，因此須要作幾種處理，這裏參考博客：https://www.cnblogs.com/panhouye/archive/2017/04/23/6751710.html

下面是我弄好的一個選擇文件的Activity，爲了方便，使用了靜態變量設置回調接口，因此直接調用startActivity方法，便可啓動選擇文件流程，並在回調接口中返回選中的文件的絕對路徑，很是方便。

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
import android.text.TextUtils;
import android.widget.Toast;

import com.imxiaoyu.common.base.ui.BaseActivity;
import com.imxiaoyu.common.impl.OnStringListener;
import com.imxiaoyu.common.utils.ALog;
import com.imxiaoyu.common.utils.ToastUtils;

import java.io.File;

import com.example.mp3editor.R;
import com.example.mp3editor.common.impl.OnMusicListener;
import com.example.mp3editor.common.util.MusicUtil;
import com.example.mp3editor.module.index.entity.MusicEntity;

/**
 * 選擇音樂文件
 * Created by Admin on 2017/11/18.
 */

public class SelectFileActivity extends BaseActivity {
    /**
     * 常量
     */
    public final static int FILE_SELECT_CODE = 0x100;
    public final static String ACTIVITY_TYPE = "ACTIVITY_TYPE";

    /**
     * 變量
     */
    private int type = 0;//0-音樂 1-視頻
    /**
     * 接口
     */
    private static OnStringListener onStringListener;

    @Override
    protected int getLayoutId() {
        return R.layout.activity_select_file;
    }

    public static void startActivity(Activity activity, OnMusicListener listener) {
        activity.startActivity(new Intent(activity, SelectFileActivity.class));
    }

    public static void startActivity(Activity activity, int type, OnStringListener listener) {
        onStringListener = listener;
        Intent intent = new Intent(activity, SelectFileActivity.class);
        intent.putExtra(ACTIVITY_TYPE, type);
        activity.startActivity(intent);
    }

    @Override
    protected void initData() {
        type = getIntent().getIntExtra(ACTIVITY_TYPE, 0);
    }

    @Override
    protected void initView() {

    }

    @Override
    protected void onCreateActivity() {
        selectFile();
    }

    public void finish() {
        onStringListener = null;
        super.finish();
    }

    /**
     * 調用文件選擇軟件來選擇文件
     **/
    public void selectFile() {
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        if (type == 0) {
            intent.setType("audio/*");
        } else {
            intent.setType("video/*");
        }
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        try {
            startActivityForResult(Intent.createChooser(intent, getString(R.string.please_select_a_file)), FILE_SELECT_CODE
            );
        } catch (android.content.ActivityNotFoundException ex) {
            // Potentially direct the user to the Market with a Dialog
            Toast.makeText(getActivity(), getString(R.string.please_install_the_file_manager), Toast.LENGTH_SHORT)
                    .show();
        }
    }


    /**
     * 根據返回選擇的文件，來進行上傳操做
     **/
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (resultCode == Activity.RESULT_OK) {
            String path;
            Uri uri = data.getData();
            if ("file".equalsIgnoreCase(uri.getScheme())) {//使用第三方應用打開
                path = uri.getPath();
                callback(path);
                return;
            }
            if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT) {//4.4之後
                path = getPath(this, uri);
                callback(path);
            } else {//4.4如下下系統調用方法
                path = getRealPathFromURI(uri);
                callback(path);
            }
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    private void callback(String path) {
        if (onStringListener != null) {
            onStringListener.onClick(path);
        }
        finish();
    }

    public String getRealPathFromURI(Uri contentUri) {
        String res = null;
        String[] proj = { MediaStore.Images.Media.DATA };
        Cursor cursor = getContentResolver().query(contentUri, proj, null, null, null);
        if(null!=cursor&&cursor.moveToFirst()){;
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            res = cursor.getString(column_index);
            cursor.close();
        }
        return res;
    }
    /**
     * 專爲Android4.4設計的從Uri獲取文件絕對路徑，之前的方法已很差使
     */
    @SuppressLint("NewApi")
    public String getPath(final Context context, final Uri uri) {

        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

        // DocumentProvider
        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
            // ExternalStorageProvider
            if (isExternalStorageDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                if ("primary".equalsIgnoreCase(type)) {
                    return Environment.getExternalStorageDirectory() + "/" + split[1];
                }
            }
            // DownloadsProvider
            else if (isDownloadsDocument(uri)) {

                final String id = DocumentsContract.getDocumentId(uri);
                final Uri contentUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

                return getDataColumn(context, contentUri, null, null);
            }
            // MediaProvider
            else if (isMediaDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                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;
                }

                final String selection = "_id=?";
                final String[] selectionArgs = new String[]{split[1]};

                return getDataColumn(context, contentUri, selection, selectionArgs);
            }
        }
        // MediaStore (and general)
        else if ("content".equalsIgnoreCase(uri.getScheme())) {
            return getDataColumn(context, uri, null, null);
        }
        // File
        else if ("file".equalsIgnoreCase(uri.getScheme())) {
            return uri.getPath();
        }
        return null;
    }
    /**
     * Get the value of the data column for this Uri. This is useful for
     * MediaStore Uris, and other file-based ContentProviders.
     *
     * @param context       The context.
     * @param uri           The Uri to query.
     * @param selection     (Optional) Filter used in the query.
     * @param selectionArgs (Optional) Selection arguments used in the query.
     * @return The value of the _data column, which is typically a file path.
     */
    public String getDataColumn(Context context, Uri uri, String selection,
                                String[] selectionArgs) {

        Cursor cursor = null;
        final String column = "_data";
        final String[] projection = {column};

        try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                    null);
            if (cursor != null && cursor.moveToFirst()) {
                final int column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }

    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    public boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri.getAuthority());
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is MediaProvider.
     */
    public boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is DownloadsProvider.
     */
    public boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
    }

}