简介：示例代码day1「layout部分」<?xml version="1.0" encoding="utf 8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <EditText android:id="@+id/et1" android:layout_width="200dp" android:layout_height="50dp" android:hint="请输入数字" android:textSize="20sp"/> <Spinner android:id="@+id/spinnner" android:entries="@array/lxy" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <EditText android:id="@+id/et2" android:layout_width="200dp" android:layout_height="50dp" android:hint="请输入数字" android:textSize="20sp"/> <Button android:id="@+id/btn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="计算" android:textSize="20sp"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="计算结果如下👇" android:textSize="30dp"/> <TextView android:id="@+id/txt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="" android:textSize="25sp"/> </LinearLayout>array「values部分」<?xml version="1.0" encoding="utf 8"?> <resources> <string array name="lxy"> <item>+</item> <item> </item> <item>*</item> <item>/</item> <item>%</item> </string array> </resources>MainActivity变量private EditText et1,et2; private TextView txt;主代码Spinner spinner = (Spinner) findViewById(R.id.spinnner); spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { String result = parent.getItemAtPosition(position).toString(); Toast.makeText(MainActivity.this,result,Toast.LENGTH_SHORT).show(); } @Override public void onNothingSelected(AdapterView<?> parent) { } }); Spinner operatorSpinner = findViewById(R.id.spinnner); ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.lxy, android.R.layout.simple_spinner_item); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); operatorSpinner.setAdapter(adapter); Button calculateButton = findViewById(R.id.btn); calculateButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { et1 = findViewById(R.id.et1); et2 = findViewById(R.id.et2); txt = findViewById(R.id.txt); double num1 = Double.parseDouble(et1.getText().toString()); double num2 = Double.parseDouble(et2.getText().toString()); Spinner operatorSpinner = findViewById(R.id.spinnner); String operator = operatorSpinner.getSelectedItem().toString(); double result = 0; switch (operator) { case "+": result = num1 + num2; break; case " ": result = num1 num2; break; case "*": result = num1 * num2; break; case "/": result = num1 / num2; break; case "%": result = num1 % num2; break; } txt.setText(String.valueOf(result)); } });

简介：简易布局文件activity_main<?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" tools:context=".MainActivity"> <Button android:id="@+id/secbtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="跳转到第二个Activity" /> </LinearLayout>layout1<?xml version="1.0" encoding="utf 8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="这是layout1" android:textSize="30dp"/> </LinearLayout>java类MainActivitypackage com.example.demo1; import androidx.appcompat.app.AppCompatActivity; import android.annotation.SuppressLint; 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.layout1); } }IntentActivityimport android.annotation.SuppressLint; import android.content.ComponentName; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; public class IntentActivity extends MainActivity { private Button secbtn; @SuppressLint("MissingInflatedId") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); secbtn = (Button) findViewById(R.id.secbtn); secbtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //实现activity跳转 显示意图跳转 /* Intent intent=new Intent(); ComponentName component=new ComponentName(IntentActivity.this,MainActivity.class); intent.setComponent(component); startActivity(intent); */ //隐式意图跳转 Intent intent = new Intent(); //通过Action属性进行查找对应activity intent.setAction("android.intent.newland.MY_ACTION"); startActivity(intent); } }); }AndroidManifest<?xml version="1.0" encoding="utf 8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"> <application android:allowBackup="true" android:dataExtractionRules="@xml/data_extraction_rules" android:fullBackupContent="@xml/backup_rules" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/Theme.Demo1" tools:targetApi="31"> <activity android:name=".IntentActivity" android:exported="true"> <intent filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent filter> </activity> <activity android:name=".MainActivity" android:exported="true"> <intent filter> <action android:name="android.intent.newland.MY_ACTION" /> <category android:name="android.intent.category.DEFAULT" /> </intent filter> </activity> </application> </manifest>

简介：示例具体代码girl「drawable部分」<?xml version="1.0" encoding="utf 8"?> <animation list xmlns:android="http://schemas.android.com/apk/res/android" android:oneshot="false"> <item android:drawable="@drawable/girl_1" android:duration="100"></item> <item android:drawable="@drawable/girl_2" android:duration="100"></item> <item android:drawable="@drawable/girl_3" android:duration="100"></item> <item android:drawable="@drawable/girl_4" android:duration="100"></item> </animation list>girldonghua「layout部分」<?xml version="1.0" encoding="utf 8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <ImageView android:id="@+id/iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/girl" android:layout_marginLeft="100dp" android:layout_marginTop="20dp"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_marginTop="25dp"> <Button android:id="@+id/start" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="开始" android:layout_marginLeft="50dp"/> <Button android:id="@+id/stop" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="停止" android:layout_marginLeft="45dp"/> </LinearLayout> </LinearLayout>Main super.onCreate(savedInstanceState); setContentView(R.layout.girldonghua); iv=(ImageView) findViewById(R.id.iv); start =(Button) findViewById(R.id.start); stop =(Button) findViewById(R.id.stop); //得到AnimationDrawable对象 ad =(AnimationDrawable) iv.getBackground(); start.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (v == start) { ad.start(); }else { ad.stop(); } } }); stop.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View t) { if (t == stop){ ad.stop(); }else { ad.start(); } } }); }

简介：rotate<?xml version="1.0" encoding="utf 8"?> <! 旋转动画 > <rotate android:repeatMode="restart" android:repeatCount="infinite" android:duration="1000" android:fromDegrees="0" android:toDegrees="360" xmlns:android="http://schemas.android.com/apk/res/android"> </rotate>中心旋转android:pivotX="50%" android:pivotY="50%"

简介：前言我电脑是Mac系统（使用PD虚拟机安装Windows），在正常安装STM32CubeMX软件后出现直接闪退，就一个软件的“开屏动画”，没有正常启动软件前几天在CSDN上找到了解决方向并成功启动软件，在这里也感谢一下_Stellar【QAQ】实践解决方向我们平时在遇到问题时，一定要有一个大致的方向，明确问题，知道如何正确的提问检查Java环境配置我就是由于java环境的问题导致，java和javac版本不一样1.代码 java version javac version【如果第二个指令报错则更改成javac version】2.修改 set java_home=C:\Program Files\Java\jdk1.8.0_261 【安装JDK的根目录】 set classpath=%JAVA_HOME%\lib\tools.jar;%JAVA_HOME%\lib\dt.jar; set path=%JAVA_HOME%\bin;继续在终端输入以上两条指令查看版本是否一致；若仍然不一致通常情况下javac显示的版本为第一次配置JAVA_HOME时的版本，如果jdk版本更换存在问题，此时最方便的办法是卸载第一次配置的jdk，仅保留当前jdk。版本一致后即可，若仍然打不开则重启