Question

我正在尝试制作一个应用程序，用于创建包含用户输入文本的文件。应该使用蓝牙将相同的文件（使用相同的按钮）发送到笔记本电脑。我已经成功创建了文件但是当启用蓝牙选择接收器时，应用程序自行关闭而没有任何错误或消息

package com.example.anukool.blutt;

import android.bluetooth.BluetoothAdapter;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.net.Uri;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.List;

public class MainActivity extends AppCompatActivity {


private static final int DISCOVER_DURATION = 500;
private static final int REQUEST_BLU =1;
EditText textmsg;
Context context;

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

    textmsg=(EditText)findViewById(R.id.write);

}
public void sendViaBluetooth(View v){

    try {
        FileOutputStream fileout=openFileOutput("data.txt", MODE_PRIVATE);
        OutputStreamWriter outputWriter=new OutputStreamWriter(fileout);
        outputWriter.write(textmsg.getText().toString());
        outputWriter.close();

        Toast.makeText(getBaseContext(), "File saved successfully!",
                Toast.LENGTH_SHORT).show();

代码完全正常，直到此处，但此后，不规则性开始

        BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();

    if(btAdapter == null){
        Toast.makeText(this,"Bluetooth not supported on the             device",Toast.LENGTH_LONG).show();
    }
    else
    {
        enableBluetooth();
    }

    } catch (Exception ex) {
        Toast.makeText(this, (CharSequence) ex,Toast.LENGTH_LONG).show();
    }
}

   public void enableBluetooth() {
    Intent intent = new    Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
     intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION,DISCOVER_DURATION);
    startActivityForResult(intent,REQUEST_BLU);
}

代码甚至可以工作到上面，应用程序要求启用蓝牙，允许应用程序启用蓝牙后，应用程序关闭没有错误但蓝牙已启用

从我希望尝试打开手机的蓝牙设备列表的代码，并在点击我需要的那个之后，将文件“data.txt”发送到该蓝牙设备然而，这种情况并没有发生......

@Override
protected void onActivityResult(int requestCode,int resultCode,Intent data)    
 {
    if(resultCode == DISCOVER_DURATION && requestCode == REQUEST_BLU)
    {
        Intent intent = new Intent();
        intent.setAction(Intent.ACTION_SEND);
        intent.setType("text/plain");
        File f = new File(context.getFilesDir(),"data.txt");

        if(f.exists())
        {
            Toast.makeText(context, "command file created successfully", Toast.LENGTH_LONG).show();
        }
        else
        {
            Toast.makeText(context, "command file not created.", Toast.LENGTH_LONG).show();
        }

        intent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(f));

        PackageManager pm = getPackageManager();
        List<ResolveInfo> appsList = pm.queryIntentActivities(intent,0);

        if(appsList.size() >0)
        {
            String packageName = null;
            String className = null;
            boolean found = false;

            for(ResolveInfo info : appsList)
            {
                packageName = info.activityInfo.packageName;
                if(packageName.equals("com.android.bluetooth"))
                {
                    className = info.activityInfo.name;
                    found = true;
                    break;
                }
            }
            if(!found)
            {
                Toast.makeText(this,"Bluetooth not found",Toast.LENGTH_LONG).show();
            }
            else
            {
                intent.setClassName(packageName,className);
                startActivity(intent);
            }
        }
        else
        {
            Toast.makeText(this,"Bluetooth   cancelled",Toast.LENGTH_LONG).show();
        }
    }
    }
}

我是一个完整的新手，并没有在android studio中获得蓝牙工具的经验：p

通过蓝牙创建和发送文件（android studio）

0 个答案: