第七周作业
1.三个界面,界面1点击按钮使用显式意图开启界面2.
界面2点击按钮隐式意图开启界面3
要求,按钮点击功能使用setOnclickListener方式
2.在界面1做一个按钮开启浏览器访问百度
<LinearLayout 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" tools:context=".MainActivity" android:orientation="vertical" > <Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="显式意图开启界面2" android:onClick="click1" /> <Button android:id="@+id/btn2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="隐式意图开启界面3" android:onClick="click2" /> <Button android:id="@+id/btn3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="开启浏览器访问百度" android:onClick="click3" /> </LinearLayout>
package com.example.myapplication; import android.net.Uri; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.util.Log; import android.view.Menu; import android.view.View; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.e("MainActivity", "调用oncreate");//在logcat里输出,标签为MainActivity,提示信息为调用oncreate } @Override protected void onStart() { // TODO Auto-generated method stub super.onStart(); Log.e("MainActivity", "调用onstart"); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); Log.e("MainActivity", "调用onresume"); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); Log.e("MainActivity", "调用onpause"); } @Override protected void onStop() { // TODO Auto-generated method stub super.onStop(); Log.e("MainActivity", "调用onstop"); } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); Log.e("MainActivity", "调用ondestroy"); } @Override protected void onRestart() { // TODO Auto-generated method stub super.onRestart(); Log.e("MainActivity", "调用onRestart"); } //使用显式意图开启界面2(一般同一个应用程序 用显式意图) public void click1(View view){ Intent intent=new Intent(this,SecondActivity.class); startActivity(intent); } //使用隐式意图开启界面3(不同应用程序,用隐式意图,例如开启浏览器、手机照相机等) public void click2(View view){ Intent intent=new Intent(); intent.setAction("cn.itcast.START_ACTIVITY"); startActivity(intent); } public void click3(View view){ Intent intent=new Intent(); intent.setAction("android.intent.action.VIEW"); intent.setData(Uri.parse("http://www.baidu.com")); startActivity(intent); } }
<RelativeLayout 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" tools:context=".MainActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="界面2" /> </RelativeLayout>
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class SecondActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); } }
<RelativeLayout 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" tools:context=".ThirdActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="界面3" /> </RelativeLayout>
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class ThirdActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_third); } }
3.2个edittext,4个按钮 一个textview,实现简单计算器
提示1:如何获取edittext上的数据?
String num1=((EditText)(findViewById(R.id.et1))).getText().toString();//获取et1上面的文本,并转成字符串
提示2:字符串如何转int
int n1=Integer.parseInt(num1);
提示3:如何把计算结果显示在textview上?
TextView tv1=(TextView)findViewById(R.id.tv1);//获取控件
tv1.setText("1233213");//用settext方法赋值
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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=".Main2Activity" android:layout_margin="20dp"> <TextView android:id="@+id/tv1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="数字:" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="15dp"/> <EditText android:id="@+id/et1" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入数字" android:textSize="25sp" android:textColorHint="#E91313" android:maxLines="1" android:scrollHorizontally="true" android:layout_toRightOf="@+id/tv1"/> <TextView android:id="@+id/tv2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="数字:" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="25dp" android:layout_below="@id/tv1"/> <EditText android:id="@+id/et2" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入数字" android:textSize="25sp" android:textColorHint="#E91313" android:maxLines="1" android:scrollHorizontally="true" android:layout_toRightOf="@+id/tv1" android:layout_below="@id/et1"/> <Button android:id="@+id/btn_1" android:layout_width="100dp" android:layout_height="100dp" android:text="+" android:textColor="#000000" android:textSize="50sp" android:layout_below="@id/et2" android:layout_marginTop="100dp" android:layout_margin="10dp" android:layout_alignLeft="@id/et2" /> <Button android:id="@+id/btn_2" android:layout_width="100dp" android:layout_height="100dp" android:text="-" android:textColor="#000000" android:textSize="50sp" android:layout_below="@id/et2" android:layout_toRightOf="@id/btn_1" /> <Button android:id="@+id/btn_3" android:layout_width="100dp" android:layout_height="100dp" android:layout_below="@id/btn_1" android:layout_margin="10dp" android:text="*" android:textColor="#000000" android:textSize="50sp" android:layout_alignLeft="@id/et2" /> <Button android:id="@+id/btn_4" android:layout_width="100dp" android:layout_height="100dp" android:layout_below="@id/btn_1" android:layout_toRightOf="@id/btn_3" android:text="/" android:textColor="#000000" android:textSize="50sp" android:layout_alignTop="@id/btn_3" /> <TextView android:id="@+id/tv3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/btn_3" android:layout_margin="20dp" android:text="结果是:" android:textSize="45sp" android:textColor="#000000" android:textStyle="italic"/> </RelativeLayout>
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.TextView; public class Main2Activity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); //+ findViewById(R.id.btn_1).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String num1=((EditText)(findViewById(R.id.et1))).getText().toString(); String num2=((EditText)(findViewById(R.id.et2))).getText().toString(); int n1=Integer.parseInt(num1); int n2=Integer.parseInt(num2); int n3=n1+n2; TextView tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //- findViewById(R.id.btn_2).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String num1=((EditText)(findViewById(R.id.et1))).getText().toString(); String num2=((EditText)(findViewById(R.id.et2))).getText().toString(); int n1=Integer.parseInt(num1); int n2=Integer.parseInt(num2); int n3=n1-n2; TextView tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //* findViewById(R.id.btn_3).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String num1=((EditText)(findViewById(R.id.et1))).getText().toString(); String num2=((EditText)(findViewById(R.id.et2))).getText().toString(); int n1=Integer.parseInt(num1); int n2=Integer.parseInt(num2); int n3=n1*n2; TextView tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //除 findViewById(R.id.btn_4).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String num1=((EditText)(findViewById(R.id.et1))).getText().toString(); String num2=((EditText)(findViewById(R.id.et2))).getText().toString(); int n1=Integer.parseInt(num1); int n2=Integer.parseInt(num2); int n3=n1/n2; TextView tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); } }