Java 介绍屏幕中的ArrayIndexOutofBoundsSexception
我在这篇文章中描述了一个类似的问题。这里没有答案- 但是,在我的应用程序中有4张欢迎幻灯片,应用程序仅显示其中的2张。第三个有一个错误。我的代码:Java 介绍屏幕中的ArrayIndexOutofBoundsSexception,java,android,android-studio,android-logcat,Java,Android,Android Studio,Android Logcat,我在这篇文章中描述了一个类似的问题。这里没有答案- 但是,在我的应用程序中有4张欢迎幻灯片,应用程序仅显示其中的2张。第三个有一个错误。我的代码: public class WelcomeActivity extends AppCompatActivity { private ViewPager viewPager; private MyViewPagerAdapter myViewPagerAdapter; private LinearLayout dotsLayou
public class WelcomeActivity extends AppCompatActivity {
private ViewPager viewPager;
private MyViewPagerAdapter myViewPagerAdapter;
private LinearLayout dotsLayout;
private TextView[] dots;
private int[] layouts;
private Button btnSkip, btnNext;
private PrefManager prefManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Checking for first time launch - before calling setContentView()
prefManager = new PrefManager(this);
if (!prefManager.isFirstTimeLaunch()) {
launchHomeScreen();
finish();
}
// Making notification bar transparent
if (Build.VERSION.SDK_INT >= 21) {
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
}
setContentView(R.layout.activity_welcome);
viewPager = (ViewPager) findViewById(R.id.view_pager);
dotsLayout = (LinearLayout) findViewById(R.id.layoutDots);
btnSkip = (Button) findViewById(R.id.btn_skip);
btnNext = (Button) findViewById(R.id.btn_next);
// layouts of all welcome sliders
// add few more layouts if you want
layouts = new int[]{
R.layout.welcome_slide1,
R.layout.welcome_slide2,
R.layout.welcome_slide3,
R.layout.welcome_slide4};
// adding bottom dots
addBottomDots(0);
// making notification bar transparent
changeStatusBarColor();
myViewPagerAdapter = new MyViewPagerAdapter();
viewPager.setAdapter(myViewPagerAdapter);
viewPager.addOnPageChangeListener(viewPagerPageChangeListener);
btnSkip.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
launchHomeScreen();
}
});
btnNext.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// checking for last page
// if last page home screen will be launched
int current = getItem(+1);
if (current < layouts.length) {
// move to next screen
viewPager.setCurrentItem(current);
} else {
launchHomeScreen();
}
}
});
}
private void addBottomDots(int currentPage) {
dots = new TextView[layouts.length];
int[] colorsActive = getResources().getIntArray(R.array.array_dot_active);
int[] colorsInactive = getResources().getIntArray(R.array.array_dot_inactive);
dotsLayout.removeAllViews();
for (int i = 0; i < dots.length; i++) {
dots[i] = new TextView(this);
dots[i].setText(Html.fromHtml("•"));
dots[i].setTextSize(35);
dots[i].setTextColor(colorsInactive[currentPage]);
dotsLayout.addView(dots[i]);
}
if (dots.length > 0)
dots[currentPage].setTextColor(colorsActive[currentPage]);
}
private int getItem(int i) {
return viewPager.getCurrentItem() + i;
}
private void launchHomeScreen() {
prefManager.setFirstTimeLaunch(false);
startActivity(new Intent(WelcomeActivity.this, MainActivity.class));
finish();
}
// viewpager change listener
ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
addBottomDots(position);
// changing the next button text 'NEXT' / 'GOT IT'
if (position == layouts.length - 1) {
// last page. make button text to GOT IT
btnNext.setText(getString(R.string.start));
btnSkip.setVisibility(View.GONE);
} else {
// still pages are left
btnNext.setText(getString(R.string.next));
btnSkip.setVisibility(View.VISIBLE);
}
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
};
/**
* Making notification bar transparent
*/
private void changeStatusBarColor() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
Window window = getWindow();
window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
window.setStatusBarColor(Color.TRANSPARENT);
}
}
/**
* View pager adapter
*/
public class MyViewPagerAdapter extends PagerAdapter {
private LayoutInflater layoutInflater;
public MyViewPagerAdapter() {
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = layoutInflater.inflate(layouts[position], container, false);
container.addView(view);
return view;
}
@Override
public int getCount() {
return layouts.length;
}
@Override
public boolean isViewFromObject(View view, Object obj) {
return view == obj;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
View view = (View) object;
container.removeView(view);
}
}
}
关于你的问题
dots[i].setTextColor(colorsInactive[currentPage]);
您可以从参考资料中获得您的颜色处于活动状态
int[] colorsInactive = getResources().getIntArray(R.array.array_dot_inactive);
您可以在src/main/res/arrays.xml或类似名称的文件中找到这些文件。此处定义的数组的名称为“活动”“数组”\u dot\u[in]且仅包含两个元素。要使代码正常工作,您需要向这些数组添加两种颜色,或者更改代码本身以反映只有两种颜色的事实
一种方法是使用产生相同值(0为偶数,1为奇数)的%2
或&1
:
您能为我们识别第107行吗?您知道
R.array.array\u dot\u[in]active
的内容吗?第107行-dots[i].setTextColor(colorsInactive[currentPage]);是否将currentPage变量设置为高于colorsInactive数组的长度?也许您应该使用System.out.println(colorsInactive.length)查看数组的实际大小;
int[] colorsInactive = getResources().getIntArray(R.array.array_dot_inactive);
dots[i].setTextColor(colorsInactive[currentPage & 1]);