Viewpager2+Fragment+指示器
- 效果展示:
- MainActivity.java
java
package com.huawei.myviewpager;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.viewpager2.widget.ViewPager2;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import com.huawei.myviewpager.adapter.MyFragmentPagerAdapter;
import com.huawei.myviewpager.fragment.FirstFragment;
import com.huawei.myviewpager.fragment.SecondFragment;
import com.huawei.myviewpager.fragment.ThirdFragment;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private MyFragmentPagerAdapter mAdapter;
private ViewPager2 mViewpager;
private List<Fragment> mList;
private LinearLayout mPointIndicator;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mList = new ArrayList<>();
mList.add(new FirstFragment());
mList.add(new SecondFragment());
mList.add(new ThirdFragment());
mAdapter = new MyFragmentPagerAdapter(this, mList);
initView();
}
private void initView() {
mViewpager = findViewById(R.id.vp2);
mViewpager.setAdapter(mAdapter);
mPointIndicator = findViewById(R.id.fragment_indicator);
insertPoint();
mViewpager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
@Override
public void onPageSelected(int position) {
int realPosition;
if (position != 0) {
realPosition = position % 3;
} else {
realPosition = 0;
}
setSelectPoint(realPosition);
}
});
}
private void insertPoint() {
for (int i = 0; i < 3; i++) {
View point = new View(MainActivity.this);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(40, 40);
layoutParams.topMargin = 20;
if (i == 0) {
point.setBackground(getResources().getDrawable(R.drawable.indicator_point_selected));
} else {
point.setBackground(getResources().getDrawable(R.drawable.indicator_point_unselected));
}
point.setLayoutParams(layoutParams);
mPointIndicator.addView(point);
}
}
private void setSelectPoint(int realPosition) {
for (int i = 0; i < mPointIndicator.getChildCount(); i++) {
View point = mPointIndicator.getChildAt(i);
if (i == realPosition) {
point.setBackgroundResource(R.drawable.indicator_point_selected);
} else {
point.setBackgroundResource(R.drawable.indicator_point_unselected);
}
}
}
}
- activity_main.xml
xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/vp2"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<LinearLayout
android:id="@+id/fragment_indicator"
android:layout_width="40dp"
android:layout_height="100dp"
android:layout_alignParentEnd="true"
android:layout_marginEnd="32dp"
android:layout_marginTop="80dp"
android:gravity="center"
android:orientation="vertical" />
</RelativeLayout>
- MyFragmentPagerAdapter
java
package com.huawei.myviewpager.adapter;
import java.util.List;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;
public class MyFragmentPagerAdapter extends FragmentStateAdapter {
private List<Fragment> mList;
public MyFragmentPagerAdapter(@NonNull FragmentActivity fragmentActivity, List<Fragment> list) {
super(fragmentActivity);
mList = list;
}
@NonNull
@Override
public Fragment createFragment(int position) {
Fragment fragment = mList.get(position);
return fragment;
}
@Override
public int getItemCount() {
return mList.size();
}
}
- FirstFragment.java
java
public class FirstFragment extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_first, container, false);
}
}
- fragment_first.xml,三个fragment相同布局
xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY"
android:src="@drawable/img9" />
</RelativeLayout>
- indicator_point_selected.xml 指示器选中shape
xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="250dp" />
<solid android:color="#FF000000" />
<stroke android:color="#FF000000" />
</shape>
- indicator_point_unselected.xml 指示器未选中shape
xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="250dp" />
<solid android:color="#FFFFFFFF" />
<stroke
android:width="1dp"
android:color="#FF000000" />
</shape
://schemas.android.com/apk/res/android">
<corners android:radius="250dp" />
<solid android:color="#FFFFFFFF" />
<stroke
android:width="1dp"
android:color="#FF000000" />
</shape