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authorChristian Schneppe <christian@pix-art.de>2016-10-21 21:54:15 +0200
committerChristian Schneppe <christian@pix-art.de>2016-10-21 21:54:15 +0200
commit268e2bcd5e71c43a5cb53fc966128dc19144c330 (patch)
treeb686078f5b9710e540acae3f6b27292f54ff6488 /src/main/java/de/pixart/messenger/ui/widget
parent925fb008fed0d490a238169e07d862957ad93efa (diff)
Retain TextView selection after list updating
Diffstat (limited to 'src/main/java/de/pixart/messenger/ui/widget')
-rw-r--r--src/main/java/de/pixart/messenger/ui/widget/ListSelectionManager.java201
1 files changed, 201 insertions, 0 deletions
diff --git a/src/main/java/de/pixart/messenger/ui/widget/ListSelectionManager.java b/src/main/java/de/pixart/messenger/ui/widget/ListSelectionManager.java
new file mode 100644
index 000000000..4cf1a9e42
--- /dev/null
+++ b/src/main/java/de/pixart/messenger/ui/widget/ListSelectionManager.java
@@ -0,0 +1,201 @@
+package de.pixart.messenger.ui.widget;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.text.Selection;
+import android.text.Spannable;
+import android.view.ActionMode;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.widget.TextView;
+
+public class ListSelectionManager {
+
+ private static final int MESSAGE_SEND_RESET = 1;
+ private static final int MESSAGE_RESET = 2;
+ private static final int MESSAGE_START_SELECTION = 3;
+
+ private static final Handler HANDLER = new Handler(Looper.getMainLooper(), new Handler.Callback() {
+
+ @Override
+ public boolean handleMessage(Message msg) {
+ switch (msg.what) {
+ case MESSAGE_SEND_RESET: {
+ // Skip one more message queue loop
+ HANDLER.obtainMessage(MESSAGE_RESET, msg.obj).sendToTarget();
+ return true;
+ }
+ case MESSAGE_RESET: {
+ final ListSelectionManager listSelectionManager = (ListSelectionManager) msg.obj;
+ listSelectionManager.futureSelectionIdentifier = null;
+ return true;
+ }
+ case MESSAGE_START_SELECTION: {
+ final StartSelectionHolder holder = (StartSelectionHolder) msg.obj;
+ holder.listSelectionManager.futureSelectionIdentifier = null;
+ startSelection(holder.textView, holder.start, holder.end);
+ return true;
+ }
+ }
+ return false;
+ }
+ });
+
+ private static class StartSelectionHolder {
+
+ public final ListSelectionManager listSelectionManager;
+ public final TextView textView;
+ public final int start;
+ public final int end;
+
+ public StartSelectionHolder(ListSelectionManager listSelectionManager, TextView textView,
+ int start, int end) {
+ this.listSelectionManager = listSelectionManager;
+ this.textView = textView;
+ this.start = start;
+ this.end = end;
+ }
+ }
+
+ private ActionMode selectionActionMode;
+ private Object selectionIdentifier;
+ private TextView selectionTextView;
+
+ private Object futureSelectionIdentifier;
+ private int futureSelectionStart;
+ private int futureSelectionEnd;
+
+ public void onCreate(TextView textView) {
+ final CustomCallback callback = new CustomCallback(textView);
+ textView.setCustomSelectionActionModeCallback(callback);
+ }
+
+ public void onUpdate(TextView textView, Object identifier) {
+ if (SUPPORTED) {
+ CustomCallback callback = (CustomCallback) textView.getCustomSelectionActionModeCallback();
+ callback.identifier = identifier;
+ if (futureSelectionIdentifier == identifier) {
+ HANDLER.obtainMessage(MESSAGE_START_SELECTION, new StartSelectionHolder(this,
+ textView, futureSelectionStart, futureSelectionEnd)).sendToTarget();
+ }
+ }
+ }
+
+ public void onBeforeNotifyDataSetChanged() {
+ if (SUPPORTED) {
+ HANDLER.removeMessages(MESSAGE_SEND_RESET);
+ HANDLER.removeMessages(MESSAGE_RESET);
+ HANDLER.removeMessages(MESSAGE_START_SELECTION);
+ if (selectionActionMode != null) {
+ final CharSequence text = selectionTextView.getText();
+ futureSelectionIdentifier = selectionIdentifier;
+ futureSelectionStart = Selection.getSelectionStart(text);
+ futureSelectionEnd = Selection.getSelectionEnd(text);
+ selectionActionMode.finish();
+ selectionActionMode = null;
+ selectionIdentifier = null;
+ selectionTextView = null;
+ }
+ }
+ }
+
+ public void onAfterNotifyDataSetChanged() {
+ if (SUPPORTED && futureSelectionIdentifier != null) {
+ HANDLER.obtainMessage(MESSAGE_SEND_RESET, this).sendToTarget();
+ }
+ }
+
+ private class CustomCallback implements ActionMode.Callback {
+
+ private final TextView textView;
+ public Object identifier;
+
+ public CustomCallback(TextView textView) {
+ this.textView = textView;
+ }
+
+ @Override
+ public boolean onCreateActionMode(ActionMode mode, Menu menu) {
+ selectionActionMode = mode;
+ selectionIdentifier = identifier;
+ selectionTextView = textView;
+ return true;
+ }
+
+ @Override
+ public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
+ return true;
+ }
+
+ @Override
+ public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
+ return false;
+ }
+
+ @Override
+ public void onDestroyActionMode(ActionMode mode) {
+ if (selectionActionMode == mode) {
+ selectionActionMode = null;
+ selectionIdentifier = null;
+ selectionTextView = null;
+ }
+ }
+ }
+
+ private static final Field FIELD_EDITOR;
+ private static final Method METHOD_START_SELECTION;
+ private static final boolean SUPPORTED;
+
+ static {
+ Field editor;
+ try {
+ editor = TextView.class.getDeclaredField("mEditor");
+ editor.setAccessible(true);
+ } catch (Exception e) {
+ editor = null;
+ }
+ FIELD_EDITOR = editor;
+ Method startSelection = null;
+ if (editor != null) {
+ String[] startSelectionNames = {"startSelectionActionMode", "startSelectionActionModeWithSelection"};
+ for (String startSelectionName : startSelectionNames) {
+ try {
+ startSelection = editor.getType().getDeclaredMethod(startSelectionName);
+ startSelection.setAccessible(true);
+ break;
+ } catch (Exception e) {
+ startSelection = null;
+ }
+ }
+ }
+ METHOD_START_SELECTION = startSelection;
+ SUPPORTED = FIELD_EDITOR != null && METHOD_START_SELECTION != null;
+ }
+
+ public static boolean isSupported() {
+ return SUPPORTED;
+ }
+
+ public static void startSelection(TextView textView) {
+ startSelection(textView, 0, textView.getText().length());
+ }
+
+ public static void startSelection(TextView textView, int start, int end) {
+ final CharSequence text = textView.getText();
+ if (SUPPORTED && start >= 0 && end > start && textView.isTextSelectable() && text instanceof Spannable) {
+ final Spannable spannable = (Spannable) text;
+ start = Math.min(start, spannable.length());
+ end = Math.min(end, spannable.length());
+ Selection.setSelection(spannable, start, end);
+ try {
+ final Object editor = FIELD_EDITOR != null ? FIELD_EDITOR.get(textView) : textView;
+ METHOD_START_SELECTION.invoke(editor);
+ } catch (Exception e) {
+ }
+ }
+ }
+} \ No newline at end of file