使用logcat让Android应用支持查看实时日志并输出至界面显示功能

/**
Author:yangyongzhen
qq:534117529
Date:20200221
*/
package com.xxxx.xxx.activity;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class LogActivity extends BaseActivity implements View.OnClickListener {

    String cmds = "";
    StringBuilder Sb = new StringBuilder("this is log");
    private BufferedReader mReader = null;
    private Process exec;
    private int mPId;
    private String mPID;
    private boolean mRunning = true;
    EditText etlog;
    Button btnStop,btnSave,btnClear;
    RandomAccessFile randomFile = null;
    private final String DIR = CommonStatus.PATH_DIR + "/log";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        toDispPageInfo("日志查看");
        etlog = findViewById(R.id.et_logs);
        btnStop =  findViewById(R.id.btn_stop);
        btnStop.setOnClickListener(this);
        btnSave =  findViewById(R.id.btn_save);
        btnSave.setOnClickListener(this);
        btnClear =  findViewById(R.id.btn_clear);
        btnClear.setOnClickListener(this);
        mPId = android.os.Process.myPid();
        mPID = String.valueOf(mPId);
        cmds = "logcat  *:e *:d | grep "(" + mPID + ")"";;
    }

    @Override
    protected void onResume() {
        super.onResume();
        try {
            exec = Runtime.getRuntime().exec(cmds);
            mReader = new BufferedReader(new InputStreamReader(exec.getInputStream()), 1024);
            new Thread(new Runnable() {
                @Override
                public void run() {
                    String line="";
                    try {
                        while (mRunning && (line = mReader.readLine())!=null) {
                            Sb.append(line);
                            if (!mRunning) {
                                break;
                            }
                            if (line.length()==0) {
                                continue;
                            }
                            final Message msg = Message.obtain();
                            msg.what = 2;
                            msg.obj = line+ "n";
                            mhandler.sendMessage(msg);
                            Thread.sleep(100);
                        }
                    }catch (Exception e){
                        Log.e(TAG, e.toString());
                    }
                    finally {
                        Log.e(TAG, "finally");
                        Log.e(TAG, "" + mRunning);
                        if (line == null) {
                            Log.e(TAG, "line is null");
                        }
                        if (exec != null) {
                            exec.destroy();
                        }
                        if (mReader != null) {
                            try {
                                mReader.close();
                                mReader = null;
                            } catch (IOException e) {
                            }
                        }
                    }
                }
            }).start();
        } catch (IOException e) {
            e.printStackTrace();
        }
        //startShowLog();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mRunning = false;
        if (exec != null) {
            exec.destroy();
        }
        if (mReader != null) {
            try {
                mReader.close();
                mReader = null;
            } catch (IOException e) {
            }
        }
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_stop:
                mRunning = false;
                break;
            case R.id.btn_save:
                SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-ddHHmmss", Locale.CHINA);
                String date = format1.format(new Date(System.currentTimeMillis()));
                try {
                    String path = DIR + "/" + date + ".log";
                    randomFile = new RandomAccessFile(path, "rw");
                    randomFile.write(etlog.getText().toString().getBytes());
                    Toast t = Toast.makeText(mContext, "日志保存成功,path="+path, Toast.LENGTH_SHORT);
                    t.show();
                } catch (IOException e) {
                    //e.printStackTrace();
                    LogUtil.d(e.toString());
                }
                break;
            case R.id.btn_clear:
               etlog.setText("");
                break;
        }
    }

    @Override
    public int initLayout() {
        return R.layout.activity_log;
    }

    @Override
    public void initView() {
        toBack();
    }

    @Override
    public void initData() {

    }

    @SuppressLint("HandlerLeak")
    Handler mhandler = new Handler() {
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case 1:
                    break;
                case 2:
                    //显示日志
                    etlog.setMovementMethod(ScrollingMovementMethod.getInstance());
                    etlog.setSelection(etlog.getText().length(), etlog.getText().length());
                    etlog.setText(etlog.getText().append(msg.obj.toString()));
                    break;
            }
        }
    };
}