スタックオーバーフローしているプログラマ日記: 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