Saioyan梟夜

示範

XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    >

    <TextView
        android:id="@+id/t1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

JAVA

public class MainActivity extends AppCompatActivity{
    TextView t1;
String s="Ihavaanappleandtwoeggsandthreecandiesapple";//目標是印出第一個apple
String s2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        t1=(TextView)findViewById(R.id.t1);
        int c =s.indexOf("ap");//從頭開始找出第一個出現的ap

//int c =s.lastIndexOf("ap");//從頭開始找出最後一個出現的ap
        s2=s.substring(c,c+5);
        t1.setText(""+s2);
    }
}

展示

相關文章:

[Android] Android 程式設計教學

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