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
<?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" tools:context=".MainActivity"> <Button android:id="@+id/bt_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#F2B4FC" android:text="显示意图开启界面2" android:textSize="20sp" android:textColor="#000000" android:layout_marginTop="20dp" android:layout_marginLeft="10dp"/> </LinearLayout>
package com.example.homework11; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button btn1=(Button)findViewById(R.id.bt_1); btn1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent=new Intent(MainActivity.this,Main2Activity.class); startActivity(intent); } }); } }
<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" tools:context=".Main2Activity"> <Button android:id="@+id/bt_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#EEA6BF" android:text="隐式意图开启界面3" android:textSize="20sp" android:textColor="#000000" android:layout_marginLeft="10dp" android:layout_marginTop="20dp"/> </LinearLayout>
package com.example.homework11; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class Main2Activity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); Button btn2=(Button)findViewById(R.id.bt_2); btn2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent=new Intent(); intent.setAction("com.ym.second"); startActivity(intent); } }); } }
<?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" android:background="#A5D4FA" tools:context=".Main3Activity"> <TextView android:id="@+id/tv_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="界面3" android:textSize="20sp" android:layout_centerInParent="true" android:textColor="#000000"/> </RelativeLayout>
<activity android:name=".Main3Activity"> <intent-filter> <action android:name="com.ym.second" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </activity> <activity android:name=".Main2Activity" > </activity> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>
2.在界面1做一个按钮开启浏览器访问百度
<?xml version="1.0" encoding="utf-8"?> <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" /> <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.week7; import android.net.Uri; import android.os.Bundle; import android.app.Activity; import android.content.Intent; import android.view.View; import android.widget.Button; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button btn1=(Button)findViewById(R.id.btn1); btn1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent=new Intent(MainActivity.this,Main2Activity.class); 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); } }
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"?> <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" android:orientation="vertical" android:id="@+id/xb_1" tools:context=".Main4Activity"> <EditText android:id="@+id/et_1" android:layout_width="200dp" android:layout_height="wrap_content" android:layout_marginTop="100dp" android:layout_marginLeft="100dp" android:layout_marginRight="100dp" android:inputType="number" android:gravity="center" android:textSize="20sp"/> <EditText android:id="@+id/et_2" android:layout_width="200dp" android:layout_height="wrap_content" android:layout_marginLeft="100dp" android:layout_marginRight="100dp" android:inputType="number" android:gravity="center" android:textSize="20sp"/> <LinearLayout android:id="@+id/xb_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:orientation="horizontal"> <Button android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="加(+)"/> <Button android:id="@+id/btn_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="减(-)"/> <Button android:id="@+id/btn_3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="乘(*)"/> <Button android:id="@+id/btn_4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="除(/)"/> </LinearLayout> <TextView android:id="@+id/tv_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="50dp" android:layout_marginLeft="150dp" android:layout_marginRight="150dp" android:textSize="30sp" android:gravity="center" android:textColor="#06C6F7" android:text="结果为"/> </LinearLayout>
package com.example.week7; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class Main4Activity extends AppCompatActivity { private TextView tv_1; private Button btn_1,btn_2,btn_3,btn_4; private EditText et_1,et_2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main4); btn_1=(Button)this.findViewById(R.id.btn_1); btn_2=(Button)findViewById(R.id.btn_2); btn_3=(Button)findViewById(R.id.btn_3); btn_4=(Button)findViewById(R.id.btn_4); et_1=(EditText)this.findViewById(R.id.et_1); et_2=(EditText)this.findViewById(R.id.et_2); tv_1=(TextView)this.findViewById(R.id.tv_1); btn_1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String inputText1=et_1.getText().toString(); String inputText2=et_2.getText().toString(); float num1=Float.valueOf(inputText1).intValue(); float num2=Float.valueOf(inputText2).intValue(); num1=num1+num2; inputText1=String.valueOf(num1); tv_1.setText(inputText1); } }); btn_2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String inputText1=et_1.getText().toString(); String inputText2=et_2.getText().toString(); float num1=Float.valueOf(inputText1).intValue(); float num2=Float.valueOf(inputText2).intValue(); num1=num1-num2; inputText1=String.valueOf(num1); tv_1.setText(inputText1); } }); btn_3.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String inputText1=et_1.getText().toString(); String inputText2=et_2.getText().toString(); float num1=Float.valueOf(inputText1).intValue(); float num2=Float.valueOf(inputText2).intValue(); num1=num1*num2; inputText1=String.valueOf(num1); tv_1.setText(inputText1); } }); btn_4.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String inputText1=et_1.getText().toString(); String inputText2=et_2.getText().toString(); float num1=Float.valueOf(inputText1).intValue(); float num2=Float.valueOf(inputText2).intValue(); if (num2==0){ Toast.makeText(Main4Activity.this,"除数不能为0",Toast.LENGTH_LONG).show(); }else{ num1=num1/num2; inputText1=String.valueOf(num1); tv_1.setText(inputText1); } } }); } }