我是android的新手，并尝试创建一个内部有片段的活动。这个想法是片段有3个ImageButtons。单击的ImageButton会将其图像传递给活动，然后在主活动中的onClick（全屏幕ImageView）之后创建的另一个片段中显示它。问题是我无法弄清楚如何传递信息。我已经阅读过多个问题已经被问过类似于这个问题了，并且浏览了android开发者网站，但是我阅读的越多，它就变得越混乱。我也遇到了findViewById的问题，说它无法解决方法。我不知道它为什么告诉我这个，并尝试了很多东西来解决它，没有任何工作。这是我的代码，任何建议将不胜感激。
主要活动：
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity implements MainActivityFragment.CanPassData{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void passData(int value){
MainActivityFragment fragment = new MainActivityFragment();
fragment.setData(5);
getSupportFragmentManager().beginTransaction().add(R.id.fragment, fragment).commit();
//***Taken From Android Developer, I believe this is how you create a new fragment when you pass the data to the main activity****
if (fragment != null) {
fragment.getData();
} else {
MainActivityFragment newFragment = new MainActivityFragment();
Bundle args = new Bundle();
//******No idea what this is calling, pictureChosen and picture are default values taken from the website*******
args.putInt(MainActivityFragment.pictureChosen, picture);
newFragment.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment, newFragment);
transaction.addToBackStack(null);
transaction.commit();
}
//*****************************************************************************************
}
public void processData(){
MainActivityFragment fragment = (MainActivityFragment) getSupportFragmentManager().findFragmentById(R.id.fragment);
int value = fragment.getData();
}
}
片段：
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
public class MainActivityFragment extends Fragment implements View.OnClickListener {
private int data;
private CanPassData parent;
public interface CanPassData{
public void passData(int value);
}
public MainActivityFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//***findViewById is saying it cannot resolve below
setContentView(R.layout.fragment_main);
ImageButton button1 = (ImageButton) findViewById(R.id.imageButton);
ImageButton button2 = (ImageButton) findViewById(R.id.imageButton2);
ImageButton button3 = (ImageButton) findViewById(R.id.imageButton3);
button1.setOnClickListener(this);
button2.setOnClickListener(this);
button3.setOnClickListener(this);
//******************************************************************************************
return inflater.inflate(R.layout.fragment_main, container, false);
}
public void onAttach(MainActivity activity){
parent = (CanPassData) activity;
}
public void setData(int value){
data = value;
}
//***onClick also has all findViewByID as cannot resolve method, and i'm not exactly sure what to do within each case, the stuff I have in there was also taken from android developer.
@Override
public void onClick(View v){
switch (v.getId()) {
case R.id.imageButton:
ImageView box = (ImageView)findViewByID(R.id.imageButton);
Drawable name = box.getBackground().getCurrent();
Intent intent = new Intent (this, newFragment.class);
intent.putExtra("com.example.coding.assignment2", name);
startActivity(intent);
break;
case R.id.imageButton2:
box = (ImageView)findViewByID(R.id.imageButton2);
name = box.getBackground().getCurrent();
intent = new Intent (this, newFragment.class);
intent.putExtra("com.example.coding.assignment2", name);
startActivity(intent);
break;
case R.id.imageButton3:
box = (ImageView)findViewByID(R.id.imageButton3);
name = box.getBackground().getCurrent();
intent = new Intent (this, newFragment.class);
intent.putExtra("com.example.coding.assignment2", name);
startActivity(intent);
break;
}
}
public void pushData(){
parent.passData(data);
}
public int getData(){
return data;
}
}
很多方法，比如getData和pushData，我不确定如何使用它来获取主要活动的信息，这是在课堂上给我的信息。我想知道是否有一种方法只是在点击时传递drawable本身，然后将该drawable分配给新片段中的ImageView，该片段显示覆盖整个片段。我被告知我需要制作第二个片段xml，但java文件本身应该通过main活动创建。这是对的吗？
答案 0 :(得分：0)
您无法解析findViewById，因为您必须为View充气才能使用片段findViewById，如下所示：
View v = inflater.inflate(R.layout.fragment_main, parent, false);
ImageButton button1 = (ImageButton) v.findViewById(R.id.imageButton);
ImageButton button2 = (ImageButton) v.findViewById(R.id.imageButton2);
ImageButton button3 = (ImageButton) v.findViewById(R.id.imageButton3);
//call your button.setOnClickListener
return v;
无需致电setContentView()
在onClick(View v)中，您还需要致电v.findViewById()
你也可以在一个案例中取消你的变量，如果你想以这种方式使用它们，你应该在任何一个案例之前声明它们。看起来应该是这样的：
public void onClick(View v){
ImageView box=null;
Drawable name = null;
Intent intent = null;
switch(v.getId()){
case R.id.imageButton:
box = (ImageView) v.findViewByID(R.id.imageButton);
name = box.getBackground().getCurrent();
intent = new Intent (this, newFragment.class);
intent.putExtra("com.example.coding.assignment2", name);
startActivity(intent);
break;
等等