android - 执行 shell 命令并在 TextView 中获取输出

Question

我想执行一些 shell 命令 并在 TextView 中获取输出。该命令可能有一个连续的输出，如 ping 或 logcat。此外，TextView 应在实时添加命令输出时自动滚动。为此，我这样做了:

package com.example.rootapp;

import java.io.DataOutputStream;
import java.io.InputStream;

import android.app.Activity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.widget.TextView;

public class MainActivity extends Activity {
    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String[] cmdArray={"logcat -b radio"};
        try {
            runAsRoot(cmdArray);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void runAsRoot(String[] cmds) throws Exception {
        tv=(TextView)findViewById(R.id.cmdOp);
        tv.setMovementMethod(new ScrollingMovementMethod());
        Process p = Runtime.getRuntime().exec("su");
        DataOutputStream os = new DataOutputStream(p.getOutputStream());
        InputStream is = p.getInputStream();
        for (String tmpCmd : cmds) {
            os.writeBytes(tmpCmd+"\n");
            int readed = 0;
            byte[] buff = new byte[4096];
            boolean cmdRequiresAnOutput = true;
            if (cmdRequiresAnOutput) {
                while( is.available() <= 0) {
                    try { Thread.sleep(5000); } catch(Exception ex) {}
                }

                while( is.available() > 0) {
                    readed = is.read(buff);
                    if ( readed <= 0 ) break;
                    String seg = new String(buff,0,readed);   
                    tv.append(seg);
                }
            }
        }        
    }
}

这工作正常，但它不会连续更新 TextView。如您所见，我正在以 root 用户身份执行 radio logcat，输出不断生成(已在终端仿真器和 adb shell 中检查过)。但就我而言，输出不是连续添加的。它在几百行后停止。这是我的布局:

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/cmdOp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="bottom"
        android:text="@string/hello_world" />
</ScrollView>

</RelativeLayout>

输出应该继续滚动 TextView。至少这是我所期望的……请问有什么解决方法吗？

Answer 1

您可以运行命令并将命令输出显示为文本，如下所示:

public class MainActivity extends Activity {

    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv=(TextView)findViewById(R.id.cmdOp);
        tv.setText("Output :"+"\n"+runAsRoot());
    }

    public String runAsRoot() {

        try {
            // Executes the command.
            Process process = Runtime.getRuntime().exec("ls -l");

            // Reads stdout.
            // NOTE: You can write to stdin of the command using
            //       process.getOutputStream().
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader(process.getInputStream()));

            int read;
            char[] buffer = new char[4096];
            StringBuffer output = new StringBuffer();
            while ((read = reader.read(buffer)) > 0) {
                output.append(buffer, 0, read);
            }
            reader.close();

            // Waits for the command to finish.
            process.waitFor();

            return output.toString();
        } catch (IOException e) {
            throw new RuntimeException(e);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
}

注意:“su”命令仅在设备已获得 root 权限时运行。否则会抛出异常。