Android基础------Activity基础

一、通过显式意图跳转，如字面意思一样，跳转的目的地是可以明确看到的

二、通过隐式意图跳转，这种方式的跳转需要我们在AndroidManifest.xml文件中为目的Activity配置Action和CateGory

模拟账号登录，分别使用俩种方式跳转

这是启动的Activity

package com.example.myapplication.intentinner;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.myapplication.R;

public class SendMessageActivity extends AppCompatActivity {
    private Button buttonShow;
    private Button buttonHide;
    private EditText editTextAccount;
    private EditText editTextPassWord;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initListener();
    }
    
    private void initView() {
        buttonShow = findViewById(R.id.btn_send_show);
        buttonHide = findViewById(R.id.btn_send_hide);
        editTextAccount = findViewById(R.id.edit_text_account);
        editTextPassword = findViewById(R.id.edit_text_password);
    }
    
    private void initListener() {
         //通过显式意图跳转
        buttonShow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(SendMessageActivity.this, ReceiverShowActivity.class);
                String account = editTextAccount.getText().toString().trim();
                if(TextUtils.isEmpty(account)){
                    Toast.makeText(SendMessageActivity.this,"账号不能为空",Toast.LENGTH_SHORT).show();
                    return;
                }
                String password = editTextPassword.getText().toString().trim();
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(SendMessageActivity.this,"密码不能为空",Toast.LENGTH_SHORT).show();
                    return;
                }
                intent.putExtra("account",account);
                intent.putExtra("password",password);
                startActivity(intent);
            }
        });
        //通过隐式意图跳转，需要添加action和category，在AndroidManifest.xml文件对应的Activity中查看
        buttonHide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setAction("com.example.myapplication.LOGIN");
                intent.addCategory(Intent.CATEGORY_DEFAULT);
                String account = editTextAccount.getText().toString().trim();
                if(TextUtils.isEmpty(account)){
                    Toast.makeText(SendMessageActivity.this,"账号不能为空",Toast.LENGTH_SHORT).show();
                    return;
                }
                String password = editTextPassword.getText().toString().trim();
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(SendMessageActivity.this,"密码不能为空",Toast.LENGTH_SHORT).show();
                    return;
                }
                intent.putExtra("account",account);
                intent.putExtra("password",password);
                startActivity(intent);
            }
        });
    }
}

package com.example.myapplication.intentinner;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
import androidx.annotation.Nullable;
import com.example.myapplication.R;

public class ReceiverShowActivity extends Activity {
    private TextView textView;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_receiver_show);
        //通过getIntent()方法获取传过来Intent
        Intent intent = getIntent();
        String account = intent.getStringExtra("account");
        String password = intent.getStringExtra("password");
        textView = findViewById(R.id.text_view_show_result);
        textView.setText("账号为："+account+"，密码为："+password);
    }
}

package com.example.myapplication.intentinner;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
import com.example.myapplication.R;

public class ReceiverHideactivity extends AppCompatActivity {
    private TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_receiver_hide);
        //通过getIntent()方法获取传过来Intent
        Intent intent = getIntent();
        String account = intent.getStringExtra("account");
        String password = intent.getStringExtra("password");
        textView = findViewById(R.id.text_view_hide_result);
        textView.setText("账号为："+account+"，密码为："+password);
    }
}

package com.example.myapplication.intentout;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import androidx.annotation.Nullable;
import com.example.myapplication.R;
public class ThirdActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_third);
    }
    
    public void skipShowIntent(View view){
        Intent intent = new Intent();
        //这里举个例子，因为不同机型的浏览器包名可能不同，请根据具体情况而定
        intent.setClassName("com.android.browser","com.android.browser.BrowserActivity");
        startActivity(intent);
    }
    
    public void skipHideIntent(View view){
        Intent intent = new Intent();
        //这里举个例子，Action、Category和Package视情况而定
        intent.setAction("android.intent.action.VIEW");
        intent.addCategory(Intent.CATEGORY_DEFAULT);
        startActivity(intent);
    }
}

package com.example.myapplication.intentforresult;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.example.myapplication.R;

public class RequestActivity extends AppCompatActivity {
    TextView textView;
    Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_request);
        textView = findViewById(R.id.text_view_request);
        button = findViewById(R.id.btn_for_result);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(RequestActivity.this,ResponseActivity.class);
                startActivityForResult(intent,1);
            }
        });
    }
    //获取请求结果
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        String msg = data.getStringExtra("result");
        if(1 == requestCode){
            if(2 == resultCode){
                textView.setText(msg);
            }
        }
    }
}

package com.example.myapplication.intentforresult;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.myapplication.R;

public class ResponseActivity extends AppCompatActivity {
    EditText editText;
    Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_response);
        editText = findViewById(R.id.edit_text_response);
        button = findViewById(R.id.btn_back);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String msg = editText.getText().toString();
                if (TextUtils.isEmpty(msg)) {
                    Toast.makeText(ResponseActivity.this,"输入不能为空",Toast.LENGTH_SHORT).show();
                    return;
                }
                Intent intent = new Intent();
                intent.putExtra("result",msg);
                //设置结果码和数据
                setResult(2,intent);
                //不要忘了调用finish()方法结束当前Activity
                finish();
            }
        });
    }
}

package com.example.myapplication.intentwithoperate;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import com.example.myapplication.R;

public class CallPhoneActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_call_phone);
    }
    public void callPhone(View view){
        Intent intent = new Intent();
        Uri uri = Uri.parse("tel:10086");
        intent.setData(uri);
        intent.setAction("android.intent.action.CALL");
        intent.addCategory(Intent.CATEGORY_DEFAULT);
        startActivity(intent);
    }
}

package com.example.myapplication.intentwithoperate;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import com.example.myapplication.R;

public class CameraRequestActivity extends AppCompatActivity {
    Button button;
    ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera_request);
        button = findViewById(R.id.btn_camera);
        imageView = findViewById(R.id.image_camera);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setAction("android.media.action.IMAGE_CAPTURE");
                intent.addCategory(Intent.CATEGORY_DEFAULT);
                startActivityForResult(intent,1);
            }
        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        
        if(1 == requestCode){
            if(Activity.RESULT_OK == resultCode && data != null){
                //用Bitmap来接收照片
                Bitmap bitmap = data.getParcelableExtra("data");
                imageView.setImageBitmap(bitmap);
            }else if(Activity.RESULT_CANCELED == resultCode){
                Toast.makeText(this,"失败",Toast.LENGTH_SHORT).show();
            }
        }
    }
}