我正在构建的应用对 Android 具有 root 访问权限。我希望在其中一个 TextView 中显示 Logcat 日志信息，以便在我调试时它可以显示在屏幕上。
谁能给我一些想法，我可以调用哪个库/函数来访问这些日志？
谢谢
【问题讨论】：
标签： android android-logcat android-debug
这是一个blogpost，它完全可以满足您的需要。它有一个关于如何显示 Logcat 日志内容的完整代码示例。代码如下：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
class ReadLogDemo extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
Process process = Runtime.getRuntime().exec("logcat -d");
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
StringBuilder log=new StringBuilder();
String line = "";
while ((line = bufferedReader.readLine()) != null) {
log.append(line);
}
TextView tv = (TextView)findViewById(R.id.textView1);
tv.setText(log.toString());
} catch (IOException e) {
// Handle Exception
}
}
}
澄清一下，这不是我的答案，这里是original
【讨论】：
嗯，有一个解决方案可以使用this lib 记录您想要筛选的任何内容。它对我不起作用，所以我开发了自己的解决方案，您可以找到它的示例here。真的很简单，在你的项目中添加一个类 OnScreenLog
package br.com.ideiageni.onscreenlogSample;
import android.app.Activity;
import android.graphics.Color;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
/**
* Created by ariel on 07/07/2016.
*/
public class OnScreenLog {
private static int timeoutTime = 1000;
private static TextView tvLog;
private static int logCount = 0;
private static int logCountMax = 30;
private static String[] logs = new String[logCountMax];
private static int cntClicks = 0;
private static boolean visibility = false;
private static Activity activity;
private int maxClicks = 5;
public OnScreenLog(){}
public OnScreenLog(Activity activity, int ViewID){
OnScreenLog.activity = activity;
tvLog = new TextView(activity.getApplicationContext());
maintainLog("Log is working");
tvLog.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT));
tvLog.setTextColor(Color.BLACK);
tvLog.setBackgroundColor(Color.LTGRAY);
tvLog.setAlpha((float) 0.4);
View v = null;
LinearLayout linearLayout;
RelativeLayout relativeLayout;
try {
linearLayout = (LinearLayout) activity.findViewById(ViewID);
} catch (ClassCastException e) {linearLayout = null;};
try {
relativeLayout = (RelativeLayout) activity.findViewById(ViewID);
} catch (ClassCastException e) {relativeLayout = null;};
if(linearLayout != null) {
linearLayout.addView(tvLog);
v = linearLayout;
} else if(relativeLayout != null) {
relativeLayout.addView(tvLog);
v = relativeLayout;
}
if(v != null) {
v.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
cntClicks++;
timerHandler.removeCallbacks(rTimeout);
timerHandler.postDelayed(rTimeout, timeoutTime);
if (cntClicks > maxClicks-1) {
setLogVisible(!visibility);
timerHandler.removeCallbacks(rTimeout);
cntClicks = 0;
}
break;
}
return false;
}
});
}
}
public void log (String text){
String logText = text;
maintainLog(logText);
}
public void log (int text){
String logText = String.valueOf(text);
maintainLog(logText);
}
public void log (int[] text){
StringBuilder builder = new StringBuilder();
for (int i : text) {
builder.append(i);
builder.append("-");
}
String logText = builder.toString();
maintainLog(logText);
}
public void log (byte[] text){
StringBuilder builder = new StringBuilder();
for (int i : text) {
builder.append(i);
builder.append("-");
}
String logText = builder.toString();
maintainLog(logText);
}
private void maintainLog(String newText){
String logText = "";
if(logCount<logCountMax) logCount++;
for(int i=logCount-1; i>0; i--){
logs[i] = logs[i-1];
}
logs[0] = newText;
for(int i=0; i<logCount; i++){
if(i<logCount-1) logText+=logs[i]+System.getProperty("line.separator");
else logText+=logs[i];
}
tvLog.setText(logText);
}
public void clearLog(){
tvLog.setText("");
}
public void setLogVisible(boolean visibility){
if(visibility) tvLog.setVisibility(View.VISIBLE);
else tvLog.setVisibility(View.INVISIBLE);
OnScreenLog.visibility = visibility;
}
public static int getLogCountMax() {
return logCountMax;
}
public static void setLogCountMax(int logCountMax) {
OnScreenLog.logCountMax = logCountMax;
logs = new String[logCountMax];
}
public int getMaxClicks() {
return maxClicks;
}
public void setMaxClicks(int maxClicks) {
this.maxClicks = maxClicks;
}
Handler timerHandler = new Handler();
Runnable rTimeout = new Runnable() {
@Override
public void run() {
cntClicks = 0;
}
};
}
那么，例如：
public class Activity1 extends AppCompatActivity {
private OnScreenLog log;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_1);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
log = new OnScreenLog(this, R.id.content_1);
log.log("Started log on Activity 1");
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(getApplicationContext(), Activity2.class);
startActivity(intent);
log.log("Starting Activity 2");
Snackbar.make(view, "Starting Activity 2", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
其中 R.id.content_1 是您的活动的主要 LinearLayout 或 RelativeLayout 的名称。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/content_1"
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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="br.com.ideiageni.onscreenlogSample.Activity1"
tools:showIn="@layout/activity_1">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Activity 1!" />
</RelativeLayout>
工作尚未完成，但可供有需要的人使用。缺少一些有关如何使用的说明。欢迎提出建议。
【讨论】：
如果您想稍微清理一下某个主题的上述答案的输出，那么这里有一个解决方案：
**冒号可能不起作用，具体取决于您的日志格式**
while ((line = bufferedReader.readLine()) != null) {
CharSequence cs = "Mqtt:"; //topic string (the colon helps cut out false positives)
if (line.contains(cs)) {
log.append(line.substring(line.indexOf("Mqtt:"),line.length())); // Cuts out the junk at the beginning of the log
log.append("\n"); // makes log print line by line like normal
}
}
感谢@Dawid 提供了一个很好的答案！
【讨论】：