📅  最后修改于: 2020-10-11 05:47:56             🧑  作者: Mango
实施欢迎滑块屏幕是一个好主意,该屏幕介绍了应用程序的主要功能。在此滑块中,可以对应用程序进行简要介绍,用户可以在启动应用程序之前在其中滑动这些滑块(MainActivity或主页)。
在此示例中,我们将使用SharedPreferences类,该类用于保持应用程序是否首次启动的状态。如果该应用程序是首次启动,则它将在启动该应用程序之前显示滑块,否则将启动MainActivity。
使用以下代码(您的UI)在布局目录中创建一个activity_main.xml文件。
创建一个activity_welcome.xml文件并添加以下代码。用于滑块的布局。
现在,在布局目录中为welcome滑块创建布局,如welcome_slide1.xml和welcome_slide2.xml。
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- @color/dot_light_screen1
- @color/dot_light_screen2
- @color/dot_dark_screen1
- @color/dot_dark_screen2
IntroOneTimeFirstTime
NEXT
SKIP
GOT IT
Welcome to Javatpoint!
Javatpoint is passionate to offer better technical content to the world.
Android
Android is a mobile operating system developed by Google.
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创建一个PrefManager.java类,并添加以下代码。在该类中,我们使用SharedPreferences类,如果首次启动该应用程序,则该类保持首选项名称和布尔状态为true。
package example.javatpoint.com.introonetimefirsttime;
import android.content.Context;
import android.content.SharedPreferences;
public class PrefManager {
SharedPreferences pref;
SharedPreferences.Editor editor;
Context _context;
// shared pref mode
int PRIVATE_MODE = 0;
// Shared preferences file name
private static final String PREF_NAME = "welcome";
private static final String IS_FIRST_TIME_LAUNCH = "IsFirstTimeLaunch";
public PrefManager(Context context) {
this._context = context;
pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = pref.edit();
}
public void setFirstTimeLaunch(boolean isFirstTime) {
editor.putBoolean(IS_FIRST_TIME_LAUNCH, isFirstTime);
editor.commit();
}
public boolean isFirstTimeLaunch() {
return pref.getBoolean(IS_FIRST_TIME_LAUNCH, true);
}
}
在WelcomeActivity.java类文件中,添加以下代码。
在本课程中,我们将执行以下任务:
package example.javatpoint.com.introonetimefirsttime;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;
import android.support.v4.view.PagerAdapter;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
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 welcome sliders
layouts = new int[]{
R.layout.welcome_slide1,
R.layout.welcome_slide2
};
// 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 true launch MainActivity
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);
}
}
}
在MainActivity.java类中,添加以下代码。此类检查SharedPreferences返回的状态。
package example.javatpoint.com.introonetimefirsttime;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PrefManager prefManager = new PrefManager(getApplicationContext());
if(prefManager.isFirstTimeLaunch()){
prefManager.setFirstTimeLaunch(false);
startActivity(new Intent(MainActivity.this, WelcomeActivity.class));
finish();
}
}
protected void btn_Click(View view){
Toast.makeText(MainActivity.this, "clicked on button", Toast.LENGTH_LONG).show();
}
}
输出: