标签：style blog http color ar for sp div on
startActivityForResult的问题
A,B,C的启动模式都是默认的
Activity A 启动了Activity B，Activity B又启动了C，A-->B-->C, 这种情况下，A启动B要求B返回result给A
如上图所示，Intent设置了Intent.FLAG_ACTIVITY_FORWARD_RESULT标志，那么此时将会交由C向A setResult。为了避免冲突，B启动C时不得指定resultRecord>=0。
ActivityRecord sourceRecord = null; ActivityRecord resultRecord = null; if (resultTo != null) { int index = indexOfTokenLocked(resultTo); if (DEBUG_RESULTS) Slog.v( TAG, "Sending result to " + resultTo + " (index " + index + ")"); if (index >= 0) { sourceRecord = (ActivityRecord)mHistory.get(index); if (requestCode >= 0 && !sourceRecord.finishing) { resultRecord = sourceRecord; } } } int launchFlags = intent.getFlags(); if ((launchFlags&Intent.FLAG_ACTIVITY_FORWARD_RESULT) != 0 && sourceRecord != null) { // Transfer the result target from the source activity to the new // one being started, including any failures. if (requestCode >= 0) { return START_FORWARD_AND_REQUEST_CONFLICT; } resultRecord = sourceRecord.resultTo; resultWho = sourceRecord.resultWho; requestCode = sourceRecord.requestCode; sourceRecord.resultTo = null; if (resultRecord != null) { resultRecord.removeResultsLocked( sourceRecord, resultWho, requestCode); }
A-->B
如果A和B不在同一个task中，那么startActivityForResult將返回RESULT_CANCELED
如果启动的activity需要新的task，那么新启动的activity将会与其caller断开依赖关系，这个关系主要是指result反馈，A-->B,如果A是通过startActivityForResult()请求启动的，并且requestCode >=0,那么如果B是在新的task中，那么B在finish的时候将不再向A反馈result，而是在启动过程中就会向A反馈一个RESULT_CANCELED。
if (r.resultTo != null && (launchFlags&Intent.FLAG_ACTIVITY_NEW_TASK) != 0) { // For whatever reason this activity is being launched into a new // task... yet the caller has requested a result back. Well, that // is pretty messed up, so instead immediately send back a cancel // and let the new task continue launched as normal without a // dependency on its originator. Slog.w(TAG, "Activity is launching as a new task, so cancelling activity result."); sendActivityResultLocked(-1, r.resultTo, r.resultWho, r.requestCode, Activity.RESULT_CANCELED, null); r.resultTo = null; }
摘自http://blog.csdn.net/windskier/article/details/7096521
标签：style blog http color ar for sp div on
原文地址：http://www.cnblogs.com/mingfeng002/p/4063105.html
