Android ActionBar夏洛克后退按钮和智能手机后退按钮

问题：

public class Principal extends SherlockActivity {

    public static int THEME = R.style.Theme_Sherlock;
    private Button entrar;
    private Button cadastrar;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            //setTheme(Principal.THEME); //Used for theme switching in samples
            super.onCreate(savedInstanceState);
            setContentView(R.layout.home);

            entrar = (Button)findViewById(R.id.entrar); 
            entrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    startActivity(new Intent(Principal.this,LoginActivity.class)); 
                    finish();
                }
            });
            cadastrar = (Button)findViewById(R.id.cadastrar_home); 
            cadastrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    Intent intent = new Intent(Principal.this, RegisterActivity.class);
                    startActivity(intent);
                    //finish();
                }
            });
        }

public class RegisterActivity extends SherlockActivity{

    protected void onCreate(Bundle savedInstanceState) {
        setTheme(Principal.THEME); //Used for theme switching in samples
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) 
        {

        case android.R.id.home:
             // Do whatever you want, e.g. finish()
            Intent intent = new Intent(this, Principal.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
             break;

          }
        return true;
    }
}

当我在第二个活动中按下智能手机和actionbar上的“后退”按钮时，我有一个要回调的主要活动。但它总是崩溃，当我完成一个动作时它就开始工作了；在主要活动中，但如果我这样做，那么智能手机的后退按钮将无法正常工作

main活动：

public class Principal extends SherlockActivity {

    public static int THEME = R.style.Theme_Sherlock;
    private Button entrar;
    private Button cadastrar;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            //setTheme(Principal.THEME); //Used for theme switching in samples
            super.onCreate(savedInstanceState);
            setContentView(R.layout.home);

            entrar = (Button)findViewById(R.id.entrar); 
            entrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    startActivity(new Intent(Principal.this,LoginActivity.class)); 
                    finish();
                }
            });
            cadastrar = (Button)findViewById(R.id.cadastrar_home); 
            cadastrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    Intent intent = new Intent(Principal.this, RegisterActivity.class);
                    startActivity(intent);
                    //finish();
                }
            });
        }

public class RegisterActivity extends SherlockActivity{

    protected void onCreate(Bundle savedInstanceState) {
        setTheme(Principal.THEME); //Used for theme switching in samples
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) 
        {

        case android.R.id.home:
             // Do whatever you want, e.g. finish()
            Intent intent = new Intent(this, Principal.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
             break;

          }
        return true;
    }
}

secondactivity:

public class Principal extends SherlockActivity {

    public static int THEME = R.style.Theme_Sherlock;
    private Button entrar;
    private Button cadastrar;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            //setTheme(Principal.THEME); //Used for theme switching in samples
            super.onCreate(savedInstanceState);
            setContentView(R.layout.home);

            entrar = (Button)findViewById(R.id.entrar); 
            entrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    startActivity(new Intent(Principal.this,LoginActivity.class)); 
                    finish();
                }
            });
            cadastrar = (Button)findViewById(R.id.cadastrar_home); 
            cadastrar.setOnClickListener(new View.OnClickListener()
            {
                public void onClick(View v)
                {


                    Intent intent = new Intent(Principal.this, RegisterActivity.class);
                    startActivity(intent);
                    //finish();
                }
            });
        }

public class RegisterActivity extends SherlockActivity{

    protected void onCreate(Bundle savedInstanceState) {
        setTheme(Principal.THEME); //Used for theme switching in samples
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) 
        {

        case android.R.id.home:
             // Do whatever you want, e.g. finish()
            Intent intent = new Intent(this, Principal.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
             break;

          }
        return true;
    }
}

---

已经尝试了很多方法，但都不起作用，只有finish（）

在第二个活动中，只需删除您的意图和startActivity内容。只需：

case android.R.id.home:
    finish();
break;

---

finish（）将从后台堆栈中删除该活动，因此在启动新活动时不要使用它，您希望用户通过按“后退”按钮返回该活动。

在第二个活动中，只需删除您的意图和startActivity内容即可。只需：

case android.R.id.home:
    finish();
break;

---

finish（）将从后堆栈中删除该活动，因此在启动希望用户通过按back按钮返回的新活动时不要使用它。

如果不希望从

SecondActivity

重新启动主体活动，只希望第二个活动完成并返回到上一个活动。尝试在

SecondActivity

--

---

使用just

finish（）

时，您不想从

SecondActivity

重新启动您的主要活动，您只希望第二个活动完成并返回到上一个活动。尝试在

SecondActivity

--

---

只需

finish（）

谢谢，也谢谢你的答案。谢谢，也谢谢你的答案。