2020年春《移动应用开发》主观题作业答案

实用文档双语（中文+英文）登录界面系统实现的主要界面和功能实现说明输入正确的用户名和密码后可进行登录操作，如果登录错误次数超过3次则锁定登录按钮。界面跟随系统语言进行中英文切换。界面设计和核心功能的主要源码<?xmlversion="1.0"encoding="utf-8"?>

<android.support.constraint.ConstraintLayoutxmlns:android="/apk/res/android"

xmlns:app="/apk/res-auto"

android:layout_width="match_parent"

android:layout_height="match_parent">

<android.support.design.widget.AppBarLayout

android:id="@+id/abl"

android:layout_width="match_parent"

android:layout_height="wrap_content"

app:layout_constraintTop_toTopOf="parent">

<Toolbar

android:id="@+id/toolbar"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:title="@string/app_name"/>

</android.support.design.widget.AppBarLayout>

<TextView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="12dp"

android:gravity="center"

android:text="@string/login_window"

android:textColor="#000000"

android:textSize="24sp"

app:layout_constraintTop_toBottomOf="@id/abl"/>

<TextView

android:layout_width="wrap_content"

android:layout_height="50dp"

android:layout_marginStart="24dp"

android:layout_marginTop="80dp"

android:layout_marginEnd="24dp"

android:gravity="center"

android:text="@string/username"

android:textSize="16sp"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/abl"/>

<EditText

android:id="@+id/et_name"

android:layout_width="0dp"

android:layout_height="50dp"

android:layout_marginStart="120dp"

android:layout_marginTop="80dp"

android:layout_marginEnd="24dp"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/abl"/>

<TextView

android:layout_width="wrap_content"

android:layout_height="50dp"

android:layout_marginStart="24dp"

android:layout_marginTop="24dp"

android:layout_marginEnd="24dp"

android:gravity="center"

android:text="@string/password"

android:textSize="16sp"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/et_name"/>

<EditText

android:id="@+id/et_password"

android:layout_width="0dp"

android:layout_height="50dp"

android:layout_marginStart="120dp"

android:layout_marginTop="24dp"

android:layout_marginEnd="24dp"

android:inputType="textPassword"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/et_name"/>

<TextView

android:id="@+id/tv_password_error"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="12dp"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/et_password"/>

<Button

android:id="@+id/bt_exit"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginStart="24dp"

android:layout_marginTop="24dp"

android:layout_marginEnd="24dp"

android:text="@string/exit"

app:layout_constraintEnd_toStartOf="@id/bt_login"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/tv_password_error"/>

<Button

android:id="@+id/bt_login"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginStart="24dp"

android:layout_marginTop="24dp"

android:layout_marginEnd="24dp"

android:text="@string/login"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toEndOf="@id/bt_exit"

app:layout_constraintTop_toBottomOf="@id/tv_password_error"/>

</android.support.constraint.ConstraintLayout>packagecom.test.demo;

importandroid.os.Bundle;

importandroid.support.v7.app.AppCompatActivity;

importandroid.text.TextUtils;

importandroid.view.View;

importandroid.widget.EditText;

importandroid.widget.TextView;

importandroid.widget.Toast;

publicclassLoginActivityextendsAppCompatActivity{

@Override

protectedvoidonCreate(BundlesavedInstanceState){

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_login);

getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);

initUI();

}

privateintcounter=3;

privatevoidinitUI(){

finalEditTextnameView=findViewById(R.id.et_name);

finalEditTextpasswordView=findViewById(R.id.et_password);

finalTextViewpasswordErrorView=findViewById(R.id.tv_password_error);

findViewById(R.id.bt_login).setOnClickListener(newView.OnClickListener(){

@Override

publicvoidonClick(Viewv){

Stringname=nameView.getText().toString().trim();

Stringpassword=passwordView.getText().toString().trim();

if(TextUtils.isEmpty(name)||TextUtils.isEmpty(password)){

Toast.makeText(LoginActivity.this,"请输入账号或密码",Toast.LENGTH_SHORT).show();

return;

}

if(name.equals("admin")&&password.equals("admin")){

Toast.makeText(LoginActivity.this,"登录成功",Toast.LENGTH_SHORT).show();

}else{

Toast.makeText(LoginActivity.this,"账号或密码错误",Toast.LENGTH_SHORT).show();

counter--;

passwordErrorView.setText(getString(R.string.password_error_count,counter));

if(counter==0){

v.setEnabled(false);

}

}

}

});

findViewById(R.id.bt_exit).setOnClickListener(newView.OnClickListener(){

@Override

publicvoidonClick(Viewv){

System.exit(0);

}

});

}

}实验过程产生的主要问题及解决办法在获取用户名以及密码的文本时，可能由于用户在输入框前后输入了空格导致和正确密码无法匹配且较为难以发现，所以在获取密码文本时需要使用trim方法进行首位去除空格的操作拨打电话和发送短信APP系统实现的主要界面和功能实现说明通过读取系统数据库中的联系人数据展示联系人列表，并且通过intent的方式调用拨打电话和发送短信的功能。界面设计和核心功能的主要源码Activity_contacts.xml<?xmlversion="1.0"encoding="utf-8"?>

<android.support.constraint.ConstraintLayoutxmlns:android="/apk/res/android"

xmlns:app="/apk/res-auto"

xmlns:tools="/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".ContactsActivity">

<android.support.design.widget.AppBarLayout

android:id="@+id/abl"

android:layout_width="match_parent"

android:layout_height="wrap_content"

app:layout_constraintTop_toTopOf="parent">

<android.support.v7.widget.Toolbar

android:id="@+id/toolbar"

android:layout_width="match_parent"

android:layout_height="?attr/actionBarSize"

android:background="?attr/colorPrimary"

app:title="联系人列表"/>

</android.support.design.widget.AppBarLayout>

<android.support.v7.widget.RecyclerView

android:id="@+id/rv_contacts"

android:layout_width="match_parent"

android:layout_height="0dp"

android:background="#ffffff"

app:layoutManager="android.support.v7.widget.LinearLayoutManager"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintTop_toBottomOf="@id/abl"/>

</android.support.constraint.ConstraintLayout>view_contants_item.xml<?xmlversion="1.0"encoding="utf-8"?>

<android.support.constraint.ConstraintLayoutxmlns:android="/apk/res/android"

xmlns:app="/apk/res-auto"

android:layout_width="match_parent"

android:layout_height="50dp">

<TextView

android:id="@+id/tv_name"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginStart="24dp"

android:textSize="16sp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent"/>

<TextView

android:id="@+id/tv_phone"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="24dp"

android:textSize="16sp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintTop_toTopOf="parent"/>

<View

app:layout_constraintBottom_toBottomOf="parent"

android:background="#55000000"

android:layout_width="match_parent"

android:layout_height="0.5dp"/>

</android.support.constraint.ConstraintLayout>ContactsActivity.javapackagecom.test.demo;

importandroid.Manifest;

importandroid.content.Context;

importandroid.content.Intent;

importandroid.content.pm.PackageManager;

importandroid.database.Cursor;

import.Uri;

importandroid.os.Bundle;

importvider.ContactsContract;

importandroid.support.annotation.NonNull;

importandroid.support.design.widget.BottomSheetDialog;

importandroid.support.v4.app.ActivityCompat;

importandroid.support.v4.content.ContextCompat;

importandroid.support.v7.app.AppCompatActivity;

importandroid.support.v7.widget.RecyclerView;

importandroid.view.LayoutInflater;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.TextView;

importandroid.widget.Toast;

importjava.util.ArrayList;

importjava.util.List;

publicclassContactsActivityextendsAppCompatActivity{

privatestaticfinalintMY_PERMISSIONS_REQUEST_READ_CONTACTS=100;

@Override

protectedvoidonCreate(BundlesavedInstanceState){

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_contacts);

if(ContextCompat.checkSelfPermission(this,Manifest.permission.READ_CONTACTS)!=PackageManager.PERMISSION_GRANTED

||ContextCompat.checkSelfPermission(this,Manifest.permission.CALL_PHONE)!=PackageManager.PERMISSION_GRANTED){

ActivityCompat.requestPermissions(this,newString[]{Manifest.permission.READ_CONTACTS,Manifest.permission.CALL_PHONE},MY_PERMISSIONS_REQUEST_READ_CONTACTS);

}else{

initList();

}

}

@Override

publicvoidonRequestPermissionsResult(intrequestCode,@NonNullString[]permissions,@NonNullint[]grantResults){

super.onRequestPermissionsResult(requestCode,permissions,grantResults);

if(requestCode==MY_PERMISSIONS_REQUEST_READ_CONTACTS){

if(grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){

initList();

}

}

}

privatevoidinitList(){

RecyclerViewrecyclerView=findViewById(R.id.rv_contacts);

List<Contact>contactList=getContactList();

ContactsAdapteradapter=newContactsAdapter(contactList,this);

recyclerView.setAdapter(adapter);

}

privateList<Contact>getContactList(){

ArrayList<Contact>contacts=newArrayList<>();

try(CursorcontactCursor=getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null)){

if(contactCursor!=null){

while(contactCursor.moveToNext()){

intid=contactCursor.getInt(contactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.CONTACT_ID));

Stringname=contactCursor.getString(contactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));

StringphoneNumber=contactCursor.getString(contactCursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

contacts.add(newContact(id,name,phoneNumber));

}

}

}catch(SecurityExceptione){

e.printStackTrace();

}

returncontacts;

}

privateclassContactsAdapterextendsRecyclerView.Adapter<ContactsAdapter.ContactsViewHolder>{

ArrayList<Contact>data=newArrayList<>();

privateLayoutInflaterinflater;

ContactsAdapter(List<Contact>data,Contextcontext){

this.data.addAll(data);

this.inflater=LayoutInflater.from(context);

}

@NonNull

@Override

publicContactsViewHolderonCreateViewHolder(@NonNullViewGroupviewGroup,inti){

returnnewContactsViewHolder(inflater.inflate(R.layout.view_contants_item,viewGroup,false));

}

@Override

publicvoidonBindViewHolder(@NonNullContactsViewHoldercontactsViewHolder,inti){

finalContactcontact=data.get(i);

finalTextViewname=contactsViewHolder.itemView.findViewById(R.id.tv_name);

TextViewphone=contactsViewHolder.itemView.findViewById(R.id.tv_phone);

name.setText();

phone.setText(contact.phone);

contactsViewHolder.itemView.setOnClickListener(newView.OnClickListener(){

@Override

publicvoidonClick(Viewv){

finalBottomSheetDialogdialog=newBottomSheetDialog(ContactsActivity.this);

dialog.setTitle("选择操作");

Viewview=inflater.inflate(R.layout.view_bottom_sheet,null,false);

view.findViewById(R.id.call).setOnClickListener(newView.OnClickListener(){

@Override

publicvoidonClick(Viewv){

if(ActivityCompat.checkSelfPermission(ContactsActivity.this,Manifest.permission.CALL_PHONE)!=PackageManager.PERMISSION_GRANTED){

Toast.makeText(ContactsActivity.this,"没有拨打电话的权限",Toast.LENGTH_SHORT).show();

dialog.dismiss();

return;

}

Intentintent=newIntent(Intent.ACTION_CALL,Uri.parse("tel:"+contact.phone));

ContactsActivity.this.startActivity(intent);