如何使操作调用一次

本文介绍了如何使操作调用一次的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

让我们说我有无限的viewpager每个已着色。因此，对应用程序的关闭操作再次被调用，但我想的是下一次启动该操作不应该再次调用

Let's say i have unlimited viewpager and each have been colored. So on close of the app the operation again being called but what i want is for next start up that operation should not be called again

推荐答案

根据您的问题，这种讨论和项目链接，就尝试了这一点：

Based on your question, this discussion and the project link, just try this out:

在 MainActivity 添加这两个全局：

/** * {@link SharedPreferences} key for the random int array. */ public static final String KEY_RANDOM_INT_FOR_INDEX = "random_int_index"; /** * Value holding the total number of images. */ public static final int TOTAL_IMAGES = 8;

然后，在的onCreate 的 MainActivity 的末尾再次添加：

// Get a reference to the default SharedPreferences SharedPreferences defSharedPreference = PreferenceManager .getDefaultSharedPreferences(this); // Check if there is a random int for at least 1 index if (defSharedPreference.getInt(KEY_RANDOM_INT_FOR_INDEX + "_0", -1) == -1) { // Generate array of <TOTAL_IMAGES> random ints; ArrayList<Integer> allInts = new ArrayList<Integer>(); for (int i = 0; i < TOTAL_IMAGES; i++) { allInts.add(i); } // Editor instance for modifying SharedPreferences; SharedPreferences.Editor sp_editor = defSharedPreference.edit(); // Generate random ints; for (int i = 0; i < TOTAL_IMAGES; i++) { int range = allInts.size(); int pickIndex = (int) (Math.random() * range); int value = allInts.remove(pickIndex); // System.out.print("\nindex: " + i + "\t=\t" + value); // Save the random value with the key; sp_editor.putInt(KEY_RANDOM_INT_FOR_INDEX + "_" + i, value); } // Save the editors queue in the SharedPreferences; sp_editormit(); }

最后，在 onCreateView MyFragment 的补充：

// Get a reference to the default SharedPreferences SharedPreferences defSharedPreference = PreferenceManager .getDefaultSharedPreferences(getActivity()); // Calculate the index of the page from base of TOTAL_IMAGES; int pageIndexInTotalImages = (mCurrentPage - 1) % MainActivity.TOTAL_IMAGES; // Calculate the index of the random image for the page; int imageID = defSharedPreference.getInt( MainActivity.KEY_RANDOM_INT_FOR_INDEX + "_" + pageIndexInTotalImages, 0); int resourceImageID = imageID + R.drawable.image0;

假设你有的ImageView 在 myfragment_layout 设置，您可以使用加载图像：

Assuming you have the ImageView set up in myfragment_layout, you can load the image using:

＆LT; ImageView的＆GT; .setImageResource（resourceImageID）;