ui代码注释

AlarmAlertActivity.java

@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
+import android.content.DialogInterface.OnDismissListener;
+import android.content.Intent;
+import android.media.AudioManager;
+import android.media.MediaPlayer;
+import android.media.RingtoneManager;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.PowerManager;
+import android.provider.Settings;
+import android.view.Window;
+import android.view.WindowManager;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.tool.DataUtils;
+
+import java.io.IOException;
+
+// AlarmAlertActivity 是一个用于显示便签提醒的 Activity。
+public class AlarmAlertActivity extends Activity implements OnClickListener, OnDismissListener {
+    private long mNoteId; // 便签的ID。
+    private String mSnippet; // 便签的预览文本。
+    private static final int SNIPPET_PREW_MAX_LEN = 60; // 预览文本的最大长度。
+    MediaPlayer mPlayer; // 用于播放提醒声音的 MediaPlayer。
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        requestWindowFeature(Window.FEATURE_NO_TITLE); // 请求无标题栏的窗口特性。
+
+        final Window win = getWindow();
+        win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED); // 锁屏时显示窗口。
+
+        if (!isScreenOn()) {
+            win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
+                    | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
+                    | WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON
+                    | WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR); // 屏幕关闭时点亮屏幕。
+        }
+
+        Intent intent = getIntent(); // 获取启动该 Activity 的 Intent。
+
+        try {
+            mNoteId = Long.valueOf(intent.getData().getPathSegments().get(1)); // 从 Intent 中获取便签 ID。
+            mSnippet = DataUtils.getSnippetById(this.getContentResolver(), mNoteId); // 获取便签预览文本。
+            mSnippet = mSnippet.length() > SNIPPET_PREW_MAX_LEN ? mSnippet.substring(0,
+                    SNIPPET_PREW_MAX_LEN) + getResources().getString(R.string.notelist_string_info)
+                    : mSnippet; // 预览文本超出最大长度时截断。
+        } catch (IllegalArgumentException e) {
+            e.printStackTrace();
+            return;
+        }
+
+        mPlayer = new MediaPlayer(); // 初始化 MediaPlayer。
+        if (DataUtils.visibleInNoteDatabase(getContentResolver(), mNoteId, Notes.TYPE_NOTE)) {
+            showActionDialog(); // 显示操作对话框。
+            playAlarmSound(); // 播放提醒声音。
+        } else {
+            finish(); // 如果便签不可见，则结束 Activity。
+        }
+    }
+
+    // 检查屏幕是否开启。
+    private boolean isScreenOn() {
+        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
+        return pm.isScreenOn();
+    }
+
+    // 播放提醒声音。
+    private void playAlarmSound() {
+        Uri url = RingtoneManager.getActualDefaultRingtoneUri(this, RingtoneManager.TYPE_ALARM);
+        int silentModeStreams = Settings.System.getInt(getContentResolver(),
+                Settings.System.MODE_RINGER_STREAMS_AFFECTED, 0);
+
+        if ((silentModeStreams & (1 << AudioManager.STREAM_ALARM)) != 0) {
+            mPlayer.setAudioStreamType(silentModeStreams);
+        } else {
+            mPlayer.setAudioStreamType(AudioManager.STREAM_ALARM);
+        }
+        try {
+            mPlayer.setDataSource(this, url);
+            mPlayer.prepare();
+            mPlayer.setLooping(true);
+            mPlayer.start();
+        } catch (IllegalArgumentException e) {
+            e.printStackTrace();
+        } catch (SecurityException e) {
+            e.printStackTrace();
+        } catch (IllegalStateException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    // 显示操作对话框。
+    private void showActionDialog() {
+        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
+        dialog.setTitle(R.string.app_name);
+        dialog.setMessage(mSnippet);
+        dialog.setPositiveButton(R.string.notealert_ok, this);
+        if (isScreenOn()) {
+            dialog.setNegativeButton(R.string.notealert_enter, this);
+        }
+        dialog.show().setOnDismissListener(this);
+    }
+
+    // DialogInterface.OnClickListener 的实现，处理对话框按钮点击事件。
+    public void onClick(DialogInterface dialog, int which) {
+        switch (which) {
+            case DialogInterface.BUTTON_NEGATIVE:
+                Intent intent = new Intent(this, NoteEditActivity.class);
+                intent.setAction(Intent.ACTION_VIEW);
+                intent.putExtra(Intent.EXTRA_UID, mNoteId);
+                startActivity(intent);
+                break;
+            default:
+                break;
+        }
+    }
+
+    // DialogInterface.OnDismissListener 的实现，处理对话框消失事件。
+    public void onDismiss(DialogInterface dialog) {
+        stopAlarmSound();
+        finish();
+    }
+
+    // 停止提醒声音。
+    private void stopAlarmSound() {
+        if (mPlayer != null) {
+            mPlayer.stop();
+            mPlayer.release();
+            mPlayer = null;
+        }
+    }
+}