作业要求:
1、请根据课程内容实现对Activity生命周期的理解,使用log展示生命周期的状态变化;
2、根据博客:https://www.jianshu.com/p/c4cfe38a91ed的内容(进阶篇中的 “点击”),在前次作业的基础上增加列表项的单项点击功能,具体要求是:新建一个新的activity1,recycleview的某一项点击后跳转到这个新的activity1。如:点击新闻列表会跳转到新闻详情页面;
3、实现最新的activityforresult功能,具体要求如下:新建一个新的activity2,在activity1上添加按钮可收到activity2的回传值。如:新闻详情页面中点击收藏按钮可显示当前的收藏数量为N。
作业内容:
ResultActivity.java代码:
package com.example.work2;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import java.util.Calendar;
public class ResultActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
Intent intent=getIntent();
intent.putExtra("data","今天是安卓课程,老师是肖蓉。\n"+"上课的时间是:"+ Calendar.getInstance().getTime());
setResult(888,intent);
finish();
}
}
activity_item.xml代码:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
tools:context=".ItemActivity">
<TextView
android:id="@+id/itemtextView2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginEnd="32dp"
android:text="这是返回的信息"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.441"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.772" />
<TextView
android:id="@+id/itemtextView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="这是详情页面"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.529"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.153" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="查看课程信息"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/itemtextView1"
app:layout_constraintVertical_bias="0.083" />
</androidx.constraintlayout.widget.ConstraintLayout>
ItemActivity.java代码:
package com.example.work2;
import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class ItemActivity extends AppCompatActivity {
private Button button;
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
textView=findViewById(R.id.itemtextView2);
button=findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent=new Intent(ItemActivity.this,ResultActivity.class);
test.launch(intent);
}
});
}
public ActivityResultLauncher test;
{
test = registerForActivityResult(
new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
@Override
public void onActivityResult(ActivityResult result) {
if (result.getResultCode() == 888) {
Log.d("xr", "onActivityResultLauncher...");
textView.setText(result.getData().getStringExtra("data"));
}
}
});
}
}