Question

我有一个活动，使用RoboGuice打印出日志。其中有一个TextView，它显示从文件中读取的大型文本字符串。

问题是我想使用textView.append（）添加新行，但没有任何反应。 textView.setText工作正常但我不能使用它，因为文本重置很慢并且消耗了CPU。

我尝试了很多东西。在UI线程上运行它，使视图无效，使用view.post（Runnable）并在UI线程中的Handler上发布它，但没有任何帮助。

以下是代码示例：

public class DiagnosticsActivity extends RoboActionBarActivity implements LogListener {

@Inject
private LogMessageHandler logger;
@InjectView(R.id.logView)
TextView logView;
@InjectView(R.id.logScrollView)
ScrollView scrollView;

public boolean logFileReadFinished = false;
private StringBuilder textUntilReadFinished = new StringBuilder();

private File sdcard;

private class AppendRunnable implements Runnable {
    private String msg;

    private AppendRunnable(String msg) {
        this.msg = msg;
    }

    public void run() {
        logView.append(msg);
        logView.invalidate();
    }
};

@Override
protected void onResume() {
    logger.registerLogListener(this);
    readLogFile();
    scrollView.scrollTo(0, Integer.MAX_VALUE);
    synchronized (this) {
        final String stringUntilReadFinished = textUntilReadFinished.toString();
        textUntilReadFinished = new StringBuilder();
        DiagnosticsActivity.this.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Handler mHandler = new Handler();
                mHandler.post(new AppendRunnable(stringUntilReadFinished + "\n"));
            }
        });
        logFileReadFinished = true;
    }
    super.onResume();
}

@Override
protected void onPause() {
    logger.removeLogListener();
    logFileReadFinished = false;
    super.onPause();
}

/**
 * Called when the activity is first created.
 */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    setContentView(R.layout.activity_diagnostics);
    ActionBar actionBar = getSupportActionBar();
    actionBar.show();
    actionBar.setDisplayHomeAsUpEnabled(true);
    actionBar.setTitle(R.string.title_diagnostics);
    sdcard = Environment.getExternalStorageDirectory();
}

private void readLogFile() {
    FileInputStream fileInputStream = null;
    BufferedReader reader = null;
    try {
        final StringBuilder text = new StringBuilder();
        File file = new File(sdcard, LoggerImpl.logName + ".log");
        if (file.exists()) {
            try {
                fileInputStream = new FileInputStream(file);
                reader = new BufferedReader(new InputStreamReader(fileInputStream));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    text.append(line + "\n");
                }
                DiagnosticsActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        logView.setText(text);
                    }
                });
            } catch (FileNotFoundException e) {
                logger.error("Log file not found!", e);
            } catch (IOException e) {
                logger.error("Cannot read log file!", e);
            }
        }
    } finally {
        try {
            reader.close();
            fileInputStream.close();
        } catch (IOException e) {
            logger.error("Cannot close log file", e);
        }
    }
}

@Override
public void onLogEvent(final String msg, Throwable throwable) {
    synchronized (this) {
        if (logFileReadFinished) {
            DiagnosticsActivity.this.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Handler mHandler = new Handler();
                    mHandler.post(new AppendRunnable(msg + "\n"));
                }
            });
        } else {
            textUntilReadFinished.append(msg + "\n");
        }
    }
}

Answer 1

在致电msg时，您是否检查过以确保append()不为空？

作为替代方法，您可以使用以下内容更新TextView而不删除旧信息：

logView.setText(logView.getText() + msg);

以上代码段将获取当前显示的文字，附加新邮件，然后显示整个String。

使用append更新TextView并不会打印新文本

1 个答案: