return nil
适用于iPhone 6及以下版本,但不适用于iPhone 7,iPhone 7 Plus模拟器。 Xcode 8.0
exportSession中的此代码 NSURL *inputURL = [[NSBundle mainBundle] URLForResource: @"example" withExtension:@"m4a"];
AVURLAsset *assetAV = [AVURLAsset URLAssetWithURL:inputURL options:nil];
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:assetAV presetName:AVAssetExportPresetAppleM4A];
NSAssert(exportSession != nil, @"AVAssetExportSession must not be nil");
,在iPhone 7 - Plus Simulator上执行时,但不在iPhone SE,iPhone 6s ...模拟器中执行。有关详细信息,请参阅以下代码。
import pandas as pd
a = [[1,2,4],[1,3,4],[2,3,4]]
b = [[1,1,1],[1,6,4],[2,9,4]]
c = [[1,3,4],[1,1,4],[2,0,4]]
d = [[1,1,4],[1,3,4],[2,0,4]]
df1 = pd.DataFrame(a,columns=["a","b","c"])
df2 = pd.DataFrame(b,columns=["a","b","c"])
df3 = pd.DataFrame(c,columns=["a","b","c"])
for df in (df1, df2, df3):
df = df.append(df, ignore_index=True)
print df
它是雷达还是我失踪的东西?
示例项目:
答案 0 :(得分:0)
这是一个错误。
它已在Xcode 8.1 beta中修复。
Xcode 8.1 beta [AVAssetExportSession allExportPresets] iPhone 7模拟器现在返回:
AVAssetExportPreset1920x1080,
AVAssetExportPresetLowQuality,
AVAssetExportPresetAppleM4A,
AVAssetExportPreset640x480,
AVAssetExportPreset3840x2160,
AVAssetExportPresetHighestQuality,
AVAssetExportPreset1280x720,
AVAssetExportPresetMediumQuality,
AVAssetExportPreset960x540
Xcode 8.0 [AVAssetExportSession allExportPresets] iPhone 7 Simulator返回一个空数组。