【Android 性能优化】应用启动优化 ( 安卓应用启动分析 | Launcher 应用启用普通安卓应用 | 应用进程分析 )

boolean startActivitySafely(View v, Intent intent, Object tag) {
        boolean success = false;
        try {
          // 启动新的应用
            success = startActivity(v, intent, tag);
        } catch (ActivityNotFoundException e) {
            Toast.makeText(this, R.string.activity_not_found, Toast.LENGTH_SHORT).show();
            Log.e(TAG, "Unable to launch. tag=" + tag + " intent=" + intent, e);
        }
        return success;
    }

public void onClick(View v) {
  // 该从 View v 组件中获取的标签 Tag 就是 Intent
  Object tag = v.getTag();
    if (tag instanceof ShortcutInfo) {
      // 获取 Intent 对象 , 可以直接根据该对象启动应用 Activity 界面
    final Intent intent = ((ShortcutInfo) tag).intent;
  }
}

boolean startActivity(View v, Intent intent, Object tag) {
      // 设置一个启动标志
      // 查找当前任务栈中是否有与该 Activity 亲和性相同的任务栈
      // 如果有将该任务栈移动到前台 , 至于是创建新 Activity 还是复用原来 Activity , 按照该 Activity 的启动模式进行操作
      // 如果没有亲和性相同任务栈 , 创建任务栈 , 移动到前台
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        try {
            // Only launch using the new animation if the shortcut has not opted out (this is a
            // private contract between launcher and may be ignored in the future).
            boolean useLaunchAnimation = (v != null) &&
                    !intent.hasExtra(INTENT_EXTRA_IGNORE_LAUNCH_ANIMATION);
            UserHandle user = (UserHandle) intent.getParcelableExtra(ApplicationInfo.EXTRA_PROFILE);
            LauncherApps launcherApps = (LauncherApps)
                    this.getSystemService(Context.LAUNCHER_APPS_SERVICE);
            if (useLaunchAnimation) {
                ActivityOptions opts = ActivityOptions.makeScaleUpAnimation(v, 0, 0,
                        v.getMeasuredWidth(), v.getMeasuredHeight());
                if (user == null || user.equals(android.os.Process.myUserHandle())) {
                    // Could be launching some bookkeeping activity
                    // 根据 Intent 启动点击图标对应的 Activity 界面
                    startActivity(intent, opts.toBundle());
                } else {
                    launcherApps.startMainActivity(intent.getComponent(), user,
                            intent.getSourceBounds(),
                            opts.toBundle());
                }
            } else {
                if (user == null || user.equals(android.os.Process.myUserHandle())) {
                  // 真实启动应用的方法
                  // 根据 Intent 启动点击图标对应的 Activity 界面
                    startActivity(intent);
                } else {
                    launcherApps.startMainActivity(intent.getComponent(), user,
                            intent.getSourceBounds(), null);
                }
            }
            return true;
        } catch (SecurityException e) {
            Toast.makeText(this, R.string.activity_not_found, Toast.LENGTH_SHORT).show();
            Log.e(TAG, "Launcher does not have the permission to launch " + intent +
                    ". Make sure to create a MAIN intent-filter for the corresponding activity " +
                    "or use the exported attribute for this activity. "
                    + "tag="+ tag + " intent=" + intent, e);
        }
        return false;
    }