Question

我正在使用AssetFileDescriptor通过调用放置在应用程序raw / assets文件夹中的getStartOffset来获取StartOffset。

对于不存在于资产/原始文件夹中的文件，如何使用File对象获得类似的startOffset？但可以在应用商店中下载并有一个文件对象。

AssetFileDescriptor fd0 = getResources().openRawResourceFd(R.raw.lycka);
AssetFileDescriptor fd1 = getResources().openRawResourceFd(R.raw.nuyorica);

fileAoffset = (int)fd0.getStartOffset();
fileAlength = (int)fd0.getLength();
fileBoffset = (int)fd1.getStartOffset();
fileBlength = (int)fd1.getLength();

File file = new File("data/user/0/com.myapp.com/files/audio/-LGHK12NDo83k9pHakIZ.m4a");
long fileLen = file.length();
// i want startOffset from File object as getting in AssetFileDescriptor

Answer 1

如果要使用文件路径启动偏移，可以使用以下代码

public class CustomPageTransformer implements ViewPager.PageTransformer {
public void transformPage(View view, float position) {
    int pageWidth = view.getWidth();
    View imageView = view.findViewById(R.id.image_view);
    View contentView = view.findViewById(R.id.content_area);

    if (position < -1) { // [-Infinity,-1)
        // This page is way off-screen to the left
    } else if (position <= 0) { // [-1,0]
        // This page is moving out to the left

        // Counteract the default swipe
        view.setTranslationX(pageWidth * -position);
        if (contentView != null) {
            // But swipe the contentView
            contentView.setTranslationX(pageWidth * position);
        }
        if (imageView != null) {
            // Fade the image in
            imageView.setAlpha(1 + position);
        }

    } else if (position <= 1) { // (0,1]
        // This page is moving in from the right

        // Counteract the default swipe
        view.setTranslationX(pageWidth * -position);
        if (contentView != null) {
            // But swipe the contentView
            contentView.setTranslationX(pageWidth * position);
        }
        if (imageView != null) {
            // Fade the image out
            imageView.setAlpha(1 - position);
        }
    } else { // (1,+Infinity]
        // This page is way off-screen to the right
    }
}

如何在获取AssetFileDescriptor时获取File的startOffset

1 个答案: