activity跳转

创建activity的界面布局以及跳转应用

代码简单，但是不注意会有闪退问题。页面跳转后出错

第一个xml

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:gravity="center"
tools:context="com.example.jzuo.MainActivity">
<EditText
    android:id="@+id/ev_username"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="@string/ev_username" />
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <Button
        android:id="@+id/btn_jrpg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:layout_weight="1"
        android:text="@string/btn_jrpg"/>

    <Button
        android:id="@+id/btn_tc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:layout_weight="1"
        android:text="@string/btn_tc" />
</LinearLayout>

<TextView
    android:id="@+id/jgh"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="30dp" />


</LinearLayout>

第二个xml

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
android:gravity="center"
tools:context="com.example.jzuo.Main2Activity">
<TextView
    android:id="@+id/xx"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="30dp"
    android:gravity="center"/>
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <Button
        android:id="@+id/btn_y"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:layout_weight="1"
        android:text="@string/btn_y"/>

    <Button
        android:id="@+id/btn_n"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:layout_weight="1"
        android:text="@string/btn_n" />
</LinearLayout>
</LinearLayout>

第一个java

public class MainActivity extends AppCompatActivity {
private EditText ev_username;
private Button btn_jrpg;
private Button btn_tc;
private TextView jgh;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ev_username=(EditText)findViewById(R.id.ev_username);
    btn_jrpg=(Button)findViewById(R.id.btn_jrpg);
    btn_tc=(Button)findViewById(R.id.btn_tc);
    jgh=(TextView)findViewById(R.id.jgh);
    String date="";
    Intent intent=getIntent();
    String jg=intent.getStringExtra("result");
    TextView jgh=(TextView)findViewById(R.id.jgh);
    date= jg;
    jgh.setText(date);

}
public void onClick(View view){
    switch (view.getId()) {
        case R.id.btn_jrpg:
            entry();
            break;
        case R.id.btn_tc:
            finish();
            break;
    }}
private void entry(){
    Intent intent=new Intent(MainActivity.this,Main2Activity.class);
    String text = ev_username.getText().toString();
    intent.putExtra("name",text+ ":对学习java有没有信心？");
    startActivity(intent);
}
}

第二个java

public class Main2Activity extends AppCompatActivity {
private Button btn_y;
private Button btn_n;
private TextView xx;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    btn_n=(Button)findViewById(R.id.btn_n);
    btn_y=(Button)findViewById(R.id.btn_y);
    xx=(TextView)findViewById(R.id.xx);
    String data="";
    Intent intent=getIntent();
    String jg=intent.getStringExtra("name");
    TextView question=(TextView)findViewById(R.id.xx);
    data = jg;
    question.setText(data);
}
public void onClick(View view){
    switch (view.getId()) {
        case R.id.btn_y:
            answer();
            break;
        case R.id.btn_n:
            answer2();
            break;
    }}
private void answer(){
    Intent intent=new Intent(Main2Activity.this,MainActivity.class);
    String text = xx.getText().toString();
    intent.putExtra("result", ":对学习安卓有信心");
    startActivity(intent);
    finish();
}

private void answer2(){
    Intent intent=new Intent(Main2Activity.this,MainActivity.class);
    String text = xx.getText().toString();
    intent.putExtra("result", ":对学习安卓没有信心");
    startActivity(intent);
    finish();
}
}