2012年8月17日金曜日

FragmentからstartActivityForResult

FragmentからstartActivityForResultすると、戻ってきた時にActivityのonActivityResultとFragmentのonActivityResultが呼ばれるようなので。。。覚え書き

ソースコードを見るとよくわかるね。

startActivityForResult の動作

Fragment
ActivityのstartActivityFromFragmentを呼んでます。 /** * Call {@link Activity#startActivityForResult(Intent, int)} on the fragment's * containing Activity. */ public void startActivityForResult(Intent intent, int requestCode) { if (mActivity == null) { throw new IllegalStateException("Fragment " + this + " not attached to Activity"); } mActivity.startActivityFromFragment(this, intent, requestCode); }
FragmentActivity
requestCodeをビット演算させてActivityのsuper.startActivityForResultを呼んでます。 /** * Called by Fragment.startActivityForResult() to implement its behavior. */ public void startActivityFromFragment(Fragment fragment, Intent intent, int requestCode) { if (requestCode == -1) { super.startActivityForResult(intent, -1); return; } if ((requestCode&0xffff0000) != 0) { throw new IllegalArgumentException("Can only use lower 16 bits for requestCode"); } super.startActivityForResult(intent, ((fragment.mIndex+1)<<16) + (requestCode&0xffff)); }

onActivityResult の動作

FragmentActivity
requestCodeをビット演算でFragmentからstartActivityForResultActivityが実行されてるかチェックして、 FragmentのonActivityResultの呼び出しを制御しています。 /** * Dispatch incoming result to the correct fragment. */ @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { int index = requestCode>>16; if (index != 0) { index--; if (mFragments.mActive == null || index < 0 || index >= mFragments.mActive.size()) { Log.w(TAG, "Activity result fragment index out of range: 0x" + Integer.toHexString(requestCode)); return; } Fragment frag = mFragments.mActive.get(index); if (frag == null) { Log.w(TAG, "Activity result no fragment exists for index: 0x" + Integer.toHexString(requestCode)); } else { frag.onActivityResult(requestCode&0xffff, resultCode, data); } return; } super.onActivityResult(requestCode, resultCode, data); }
Fragment
/** * Receive the result from a previous call to * {@link #startActivityForResult(Intent, int)}. This follows the * related Activity API as described there in * {@link Activity#onActivityResult(int, int, Intent)}. * * @param requestCode The integer request code originally supplied to * startActivityForResult(), allowing you to identify who this * result came from. * @param resultCode The integer result code returned by the child activity * through its setResult(). * @param data An Intent, which can return result data to the caller * (various data can be attached to Intent "extras"). */ public void onActivityResult(int requestCode, int resultCode, Intent data) { }

Y.A.M の 雑記帳: Android Support Package の Fragment から startActivityForResult() を使うときの注意点

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