使用 openFileInput 读取 3gp 文件，可能吗？

Question

我正在尝试使用 openFileInput 读取一个 3gp 文件，该文件在代码中较早生成并保存在环境保存文件的位置。这甚至可能吗？如果不可能，我应该如何解决这个问题？具体方法如下：

public String readFile(String file){
        String rawdata = "";
        try{
            FileInputStream fis = openFileInput(file);
            int size = fis.available();
            byte[] buffer = new byte[size];
            fis.read(buffer);
            fis.close();
            rawdata = new String(buffer);
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(ReceiveScreen.this, "Error reading file!", Toast.LENGTH_SHORT).show();
        }
        return rawdata;
    }

这里是完整的 activity 如果有帮助的话：

package com.example.wesle.noisemachine;

import android.content.Intent;
import android.media.MediaCodec;
import android.media.MediaFormat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.AppCompatDrawableManager;
import android.view.View;
import android.widget.Button;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.os.Environment;
import android.widget.Toast;

import java.io.FileInputStream;
import java.io.IOException;

public class ReceiveScreen extends AppCompatActivity {

    private Button buttonStart, buttonStop, buttonPlay, buttonDecode;
    private MediaRecorder mediaRecorder = new MediaRecorder();
    private String outputFile;

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

        buttonStart = (Button) findViewById(R.id.buttonStart);
        buttonStop = (Button) findViewById(R.id.buttonStop);
        buttonPlay = (Button) findViewById(R.id.buttonPlay);
        buttonDecode = (Button) findViewById(R.id.buttonDecode);
        buttonStop.setEnabled(false);
        buttonPlay.setEnabled(false);
        outputFile = Environment.getExternalStorageDirectory().getAbsolutePath() + "/recording.3gp";
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        mediaRecorder.setOutputFile(outputFile);

        buttonStart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    mediaRecorder.prepare();
                    mediaRecorder.start();
                } catch (IllegalStateException ise) {
                    System.out.println("ISE Catch");
                } catch (IOException ioe) {
                    System.out.println("IO Catch");

                }
                buttonStart.setEnabled(false);
                buttonStop.setEnabled(true);


                Toast.makeText(getApplicationContext(), "Recording started", Toast.LENGTH_LONG).show();


            }
        });

        buttonStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                mediaRecorder.stop();
                mediaRecorder.release();

                buttonStop.setEnabled(false);
                buttonPlay.setEnabled(true);
                buttonStart.setEnabled(true);

                Toast.makeText(getApplicationContext(), "Recording Completed", Toast.LENGTH_LONG).show();
            }
        });

        buttonPlay.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                MediaPlayer mediaPlayer = new MediaPlayer();

                try {
                    mediaPlayer.setDataSource(outputFile);
                    mediaPlayer.prepare();
                    mediaPlayer.start();
                } catch (Exception e) {
                    System.out.println("E Catch");
                }
                Toast.makeText(getApplicationContext(), "Recording Playing", Toast.LENGTH_LONG).show();
            }
        });

        buttonDecode.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                System.out.println(readFile("recording.3gp"));

                Toast.makeText(getApplicationContext(), "Decoding", Toast.LENGTH_LONG).show();
            }
        });

        //Code for the back button
        Button backbuttonR = (Button) findViewById(R.id.backbuttonR);
        backbuttonR.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(ReceiveScreen.this, MainActivity.class));
            }
        });
    }

    public String readFile(String file){
        String rawdata = "";
        try{
            FileInputStream fis = openFileInput(file);
            int size = fis.available();
            byte[] buffer = new byte[size];
            fis.read(buffer);
            fis.close();
            rawdata = new String(buffer);
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(ReceiveScreen.this, "Error reading file!", Toast.LENGTH_SHORT).show();
        }
        return rawdata;
    }
}

Answer 1

Is this even possible

没有，因为openFileInput()和Environment没有任何关系。

how should I be approaching this problem?

使用new FileInputStream()，传入一个File对象。您已经在创建 File 对象 (outputFile)。

使用 openFileInput 读取 3gp 文件，可能吗？

using openFileInput to read a 3gp file, is it possible?

java

android

3gp