如何在片段中设置内容视图？

Question

现在我有这个片段，我想使用 setContentView，但到目前为止我找不到方法。您可以在下面的代码中看到我的案例，我没有尝试扩展布局，而是尝试将其与名为 SampleView 的视图一起使用。那么我该怎么做呢？ 提前致谢

public class largeImageScroller extends SherlockFragment {

// Physical display width and height.
private static int displayWidth = 0;
private static int displayHeight = 0;

/** Called when the activity is first created. */
public View onCreateView(LayoutInflater inflater, ViewGroup group, Bundle saved) {

        getActivity();
        // displayWidth and displayHeight will change depending on screen
        // orientation. To get these dynamically, we should hook onSizeChanged().
        // This simple example uses only landscape mode, so it's ok to get them
        // once on startup and use those values throughout.

        Display display = ((WindowManager)
getActivity().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
        displayWidth = display.getWidth();             
        displayHeight = display.getHeight();    

        // SampleView constructor must be constructed last as it needs the
        // displayWidth and displayHeight we just got.
        setContentView(new SampleView(this));
}

private static class SampleView extends View {
        private static Bitmap bmLargeImage; //bitmap large enough to be scrolled
        private static Rect displayRect = null; //rect we display to
        private Rect scrollRect = null; //rect we scroll over our bitmap with
        private int scrollRectX = 0; //current left location of scroll rect
        private int scrollRectY = 0; //current top location of scroll rect
        private float scrollByX = 0; //x amount to scroll by
        private float scrollByY = 0; //y amount to scroll by
        private float startX = 0; //track x from one ACTION_MOVE to the next
        private float startY = 0; //track y from one ACTION_MOVE to the next

        public SampleView(Context context) {
                super(context);

                // Destination rect for our main canvas draw. It never changes.
                displayRect = new Rect(0, 0, displayWidth, displayHeight);
                // Scroll rect: this will be used to 'scroll around' over the
                // bitmap in memory. Initialize as above.
                scrollRect = new Rect(0, 0, displayWidth, displayHeight);

                // Load a large bitmap into an offscreen area of memory.
                bmLargeImage = BitmapFactory.decodeResource(getResources(),
                        R.drawable.ground_floor_b);
        }

        @Override
        public boolean onTouchEvent(MotionEvent event) {

                switch (event.getAction()) {
                        case MotionEvent.ACTION_DOWN:
                                // Remember our initial down event location.
                                startX = event.getRawX();
                                startY = event.getRawY();
                                break;

                        case MotionEvent.ACTION_MOVE:
                                float x = event.getRawX();
                                float y = event.getRawY();
                                // Calculate move update. This will happen many times
                                // during the course of a single movement gesture.
                                scrollByX = x - startX; //move update x increment
                                scrollByY = y - startY; //move update y increment
                                startX = x; //reset initial values to latest
                                startY = y;
                                invalidate(); //force a redraw
                                break;
                }
                return true; //done with this event so consume it
        }

        @Override
        protected void onDraw(Canvas canvas) {

                // Our move updates are calculated in ACTION_MOVE in the opposite direction
                // from how we want to move the scroll rect. Think of this as dragging to
                // the left being the same as sliding the scroll rect to the right.
                int newScrollRectX = scrollRectX - (int)scrollByX;
                int newScrollRectY = scrollRectY - (int)scrollByY;

                // Don't scroll off the left or right edges of the bitmap.
                if (newScrollRectX < 0)
                        newScrollRectX = 0;
                else if (newScrollRectX > (bmLargeImage.getWidth() - displayWidth))
                        newScrollRectX = (bmLargeImage.getWidth() - displayWidth);

                // Don't scroll off the top or bottom edges of the bitmap.
                if (newScrollRectY < 0)
                        newScrollRectY = 0;
                else if (newScrollRectY > (bmLargeImage.getHeight() - displayHeight))
                        newScrollRectY = (bmLargeImage.getHeight() - displayHeight);

                // We have our updated scroll rect coordinates, set them and draw.
                scrollRect.set(newScrollRectX, newScrollRectY,
                        newScrollRectX + displayWidth, newScrollRectY + displayHeight);
                Paint paint = new Paint();
                canvas.drawBitmap(bmLargeImage, scrollRect, displayRect, paint);

                // Reset current scroll coordinates to reflect the latest updates,
                // so we can repeat this update process.
                scrollRectX = newScrollRectX;
                scrollRectY = newScrollRectY;
        }
}
}

Answer 1

你不要在片段中调用setContentView，实际上你需要从onCreateView返回一个View。

尝试替换：

setContentView(new SampleView(this));

有了这个：

return new SampleView(this);

Answer 2

返回你要使用的视图实例：

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.ads_tab, container, false);
    }

Answer 3

此外，从onCreateView() 调用getActivity() 也不安全。 确保在onActivityCreated() 或之后调用它，因为此时您的Fragment 与Activity 完全关联。检查Fragment 的生命周期。

Fragments

Answer 4

如前所述，您需要在片段的情况下返回视图。 但是如果你想像setContentView()一样使用它，你可以通过以下方式来使用它。

1.把这段代码sn-p放在你必须放setContentView()的地方

View v = inflater.inflate(R.layout.activity_home, container, false);

2.现在如果你想从 xml 文件中访问某些东西，你可以使用

chart = v.findViewById(R.id.chart);

3。在OnCreateView() 的末尾，你必须把

return v;

完整示例：

  public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {


    View v = inflater.inflate(R.layout.activity_home, container, false);

    chart = v.findViewById(R.id.chart);

    return v;
   }

Answer 5

在活动中我们需要使用setContentView(R.layout.main)设置视图

在片段中，我们需要覆盖 onCreateView() 以设置所需的视图。