if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      //透明状态栏
      getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
      //透明底部导航栏
      getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
     }

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
  </style>

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"
  android:clipToPadding="false"
  android:background="#795548"
  tools:context=".DefaultActivity" >

  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="18sp"
    android:textColor="#ffffff"
    android:text="@string/str" />

</ScrollView>

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"
  android:clipToPadding="false"
  android:background="#795548"
  tools:context=".DefaultActivity" >

  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="18sp"
    android:textColor="#ffffff"
    android:text="@string/str" />

</ScrollView>

<resources>

  <!-- Base application theme. -->
  <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
  </style>

</resources>

public class MainActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      //透明状态栏
      getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
      //透明导航栏
      getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
     }

    setContentView(R.layout.activity_main);



  }