Question

我正在Android上开发应用程序。

我对片段有问题，可以在下面找到代码。

其想法是让图像视图无限循环地显示图片列表。为了实现这一点，我创建了一个新的线程，以免阻塞UI线程。使用while（0 <5）语句创建一个无限循环。然后，我运行if ... else语句来检查我们要确定要转到的下一张图片。

使用处理程序来处理切换图片之间的10秒延迟。最后，另一个可运行对象负责向UI线程的发布。

这似乎是完成工作的一种非常复杂的方法，有人使用了简单的代码吗？

最重要的是，在我的代码中的某个地方，有一个错误。我找不到它，有人吗？

这是我的代码。

public class SecAct_Foto_Fragment extends Fragment {

    int counter = 0;
    View rootView;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        rootView = inflater.inflate(R.layout.sec_act_photo_layout, container, false);

        return rootView;
    }

    Thread myThread = new Thread(new Runnable() {
        @Override
        public void run() {
            while (0 < 5) {

                //so far it loops only once
                //you start with run_rocks and but_left
                final ImageView pic_view = (ImageView) rootView.findViewById(R.id.foto_groot);
                final ImageView three_but = (ImageView) rootView.findViewById(R.id.knoppen);

                //create a runnable for the picture view
                pic_view.post(new Runnable() {
                    @Override
                    public void run() {
                        //every 10 seconds, switch picture and button fragment
                        if (counter == 0) {
                            final Handler handler0 = new Handler();
                            handler0.postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    pic_view.post(new Runnable() {
                                        @Override
                                        public void run() {
                                            pic_view.setImageResource(R.drawable.run_mount);
                                        }
                                    });
                                    counter = 1;
                                }
                            }, 10000L);
                        } else if (counter == 1) {
                            final Handler handler1 = new Handler();
                            handler1.postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    pic_view.post(new Runnable() {
                                        @Override
                                        public void run() {
                                            pic_view.setImageResource(R.drawable.run_away);
                                        }
                                    });
                                    counter = 2;
                                }
                            }, 10000L);
                        } else {
                            final Handler handler2 = new Handler();
                            handler2.postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    pic_view.post(new Runnable() {
                                        @Override
                                        public void run() {
                                            pic_view.setImageResource(R.drawable.run_rocks);
                                        }
                                    });
                                    counter = 0;
                                }
                            }, 10000L);
                        }
                    }
                });

                myThread.start();
            }
        }
    });
}

Answer 1

     private class AsyncQueryRun extends AsyncTask {
    @Override
            protected Object doInBackground(Object[] objects) {
                for (...){
                     ////do what you want


                    runOnUiThread(new Runnable() {
                            @Override
                               public void run() {
                           ///do what you want to be handled by UI thread
                           }});
                  SystemClock.sleep(60); ////wait as long as you want in mili sec.
               }
    }
    @Override
            protected void onPostExecute(Object o) {
                 }
    }

Answer 2

代替上面的代码，只需使用ViewFlipper或ImageSwitcher。

您可以将视图添加到ViewFlipper并可以使用setFlipInterval（）设置延迟

请通过此链接 https://developer.android.com/reference/android/widget/ViewFlipper

Answer 3

您可以通过以下方式使用Handler：

        final ImageView pic_view = (ImageView) rootView.findViewById(R.id.foto_groot);

        private int animationCounter = 1;
        private Handler imageSwitcherHandler;
        imageSwitcherHandler = new Handler(Looper.getMainLooper());
        imageSwitcherHandler.post(new Runnable() {
            @Override
            public void run() {
                switch (animationCounter++) {
                    case 1:
                        pic_view.setImageResource(R.drawable.run_mount);

                        break;
                    case 2:
                        pic_view.setImageResource(R.drawable.run_mount2);

                        break;
                    case 3:
                        pic_view.setImageResource(R.drawable.run_mount3);
                        break;
                }
                animationCounter %= 4;
                if(animationCounter == 0 ) animationCounter = 1;

                imageSwitcherHandler.postDelayed(this, 3000);
            }
        });

Answer 4

我决定尝试@NehaK的解决方案，并使用ImageSwitcher View。

以XML添加了以下代码。

   <ImageSwitcher
        android:id="@+id/foto_groot_imageswitch"
        android:layout_width="match_parent"
        android:layout_height="220dp"
        app:srcCompat="@drawable/run_rocks"
    />

然后在我的片段中使用它。

    public class SecAct_Foto_Fragment extends Fragment {

    int counter = 0;
    View rootView;
    private ImageSwitcher pic_image_switch;
    private Handler pic_image_switch_handler;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        rootView = inflater.inflate(R.layout.sec_act_photo_layout, container, false);

        /*Animation anim_in = AnimationUtils.loadAnimation(getActivity(), R.anim.enter_from_left);
        pic_image_switch.setInAnimation(anim_in);*/

        //pic_image_switch = new ImageSwitcher(getActivity());
        pic_image_switch = (ImageSwitcher) rootView.findViewById(R.id.foto_groot_imageswitch);

        pic_image_switch.setFactory(new ViewSwitcher.ViewFactory() {
            @Override
            public View makeView() {
                ImageView imageView = new ImageView(getActivity());
                imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
                imageView.setLayoutParams(new ImageSwitcher.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
                return imageView;
            }
        });

        pic_image_switch_handler = new Handler(Looper.getMainLooper());

        pic_image_switch_handler.post(new Runnable() {
            @Override
            public void run() {
                switch (counter) {
                    case 0:
                        pic_image_switch.setImageResource(R.drawable.run_mount);
                        break;
                    case 1:
                        pic_image_switch.setImageResource(R.drawable.run_away);
                        break;
                    case 2:
                        pic_image_switch.setImageResource(R.drawable.run_rocks);
                        break;
                }
                counter += 1;
                if (counter == 3) {
                    counter = 0;
                }
                pic_image_switch.postDelayed(this, 1000);
            }
        });

        return rootView;
    }
}

无限循环-延迟-单独的线程

4 个答案: