01_activity lifecycle and Data Transmission

1. Activity lifecycle:

2. The activity starts another activity and transmits data:

package com.example.activitydemo;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;public class MainActivity extends Activity {    protected static final String EXTRA_MESSAGE = "com.example.activitydemo.MESSAGE";    public Button btnActivityChange;    public EditText editMessage;        @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        btnActivityChange = (Button) findViewById(R.id.btn1);        editMessage = (EditText) findViewById(R.id.editMessage);        btnActivityChange.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent i = new Intent(MainActivity.this, Activity2.class);                                String message = editMessage.getText().toString();                i.putExtra(EXTRA_MESSAGE, message);                                startActivity(i);            }        });    }}

package com.example.activitydemo;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;public class Activity2 extends Activity {    private Button btnBack;    private TextView textView1;    @Override    protected void onCreate(Bundle savedInstanceState) {        // TODO Auto-generated method stub        super.onCreate(savedInstanceState);        setContentView(R.layout.activity2);        btnBack = (Button) findViewById(R.id.btnBack);        textView1 = (TextView) findViewById(R.id.textView1);        Intent intent = getIntent();        textView1.setText(intent.getStringExtra(MainActivity.EXTRA_MESSAGE));        btnBack.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                finish();            }        });    }}

 

01_activity lifecycle and Data Transmission