Save and restore the app state. https://redmine.stoutner.com/issues/461

[PrivacyBrowserAndroid.git] / app / src / main / java / com / stoutner / privacybrowser / asynctasks / GetLogcat.java

diff --git a/app/src/main/java/com/stoutner/privacybrowser/asynctasks/GetLogcat.java b/app/src/main/java/com/stoutner/privacybrowser/asynctasks/GetLogcat.java
new file mode 100644 (file)
index 0000000..4722dbf
--- /dev/null
+++ b/app/src/main/java/com/stoutner/privacybrowser/asynctasks/GetLogcat.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright © 2020 Soren Stoutner <soren@stoutner.com>.
+ *
+ * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
+ *
+ * Privacy Browser is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Privacy Browser is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.stoutner.privacybrowser.asynctasks;
+
+import android.app.Activity;
+import android.os.AsyncTask;
+import android.widget.ScrollView;
+import android.widget.TextView;
+
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
+
+import com.stoutner.privacybrowser.R;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.lang.ref.WeakReference;
+
+// `Void` does not declare any parameters.  `Void` does not declare progress units.  `String` contains the results.
+public class GetLogcat extends AsyncTask<Void, Void, String> {
+    // Define the class variables.
+    private final WeakReference<Activity> activityWeakReference;
+    private int scrollViewYPositionInt;
+
+    // The public constructor.
+    public GetLogcat(Activity activity, int scrollViewYPositionInt) {
+        // Populate the weak reference to the calling activity.
+        activityWeakReference = new WeakReference<>(activity);
+
+        // Store the scrollview Y position.
+        this.scrollViewYPositionInt = scrollViewYPositionInt;
+    }
+
+    @Override
+    protected String doInBackground(Void... parameters) {
+        // Get a handle for the activity.
+        Activity activity = activityWeakReference.get();
+
+        // Abort if the activity is gone.
+        if ((activity == null) || activity.isFinishing()) {
+            return "";
+        }
+
+        // Create a log string builder.
+        StringBuilder logStringBuilder = new StringBuilder();
+
+        try {
+            // Get the logcat.  `-b all` gets all the buffers (instead of just crash, main, and system).  `-v long` produces more complete information.  `-d` dumps the logcat and exits.
+            Process process = Runtime.getRuntime().exec("logcat -b all -v long -d");
+
+            // Wrap the logcat in a buffered reader.
+            BufferedReader logBufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
+
+            // Create a log transfer string.
+            String logTransferString;
+
+            // Use the log transfer string to copy the logcat from the buffered reader to the string builder.
+            while ((logTransferString = logBufferedReader.readLine()) != null) {
+                // Append a line.
+                logStringBuilder.append(logTransferString);
+
+                // Append a line break.
+                logStringBuilder.append("\n");
+            }
+
+            // Close the buffered reader.
+            logBufferedReader.close();
+        } catch (IOException exception) {
+            // Do nothing.
+        }
+
+        // Return the logcat.
+        return logStringBuilder.toString();
+    }
+
+    // `onPostExecute()` operates on the UI thread.
+    @Override
+    protected void onPostExecute(String logcatString) {
+        // Get a handle for the activity.
+        Activity activity = activityWeakReference.get();
+
+        // Abort if the activity is gone.
+        if ((activity == null) || activity.isFinishing()) {
+            return;
+        }
+
+        // Get handles for the views.
+        TextView logcatTextView = activity.findViewById(R.id.logcat_textview);
+        SwipeRefreshLayout swipeRefreshLayout = activity.findViewById(R.id.logcat_swiperefreshlayout);
+        ScrollView scrollView = activity.findViewById(R.id.logcat_scrollview);
+
+        // Display the logcat.
+        logcatTextView.setText(logcatString);
+
+        // Update the scroll position after the text is populated.
+        logcatTextView.post(() -> {
+            // Set the scroll position.
+            scrollView.setScrollY(scrollViewYPositionInt);
+        });
+
+        // Stop the swipe to refresh animation if it is displayed.
+        swipeRefreshLayout.setRefreshing(false);
+    }
+}
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